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Off Grid Living / Camping => Off Grid Living / Alternative Housing => Utilities => Topic started by: madlabs on November 28, 2012, 08:28:59 am

Title: Electric Fence Zapper
Post by: madlabs on November 28, 2012, 08:28:59 am
Hi All,

I'm working on a electric fence zapper to keep critters, including bears, out of my orchard. Since the zappers one can buy seem too wimpy for bears, plus what fun would it be to buy one, I decided to make one myself starting with a ignition coil. Right now I am pulling a bright 1" spark. Haven't had the guts to touch it yet, I'm scared. :)
 
So, I'd like a little help confirming that what I have designed seems reasonable. I am using a 7aH, 12V SLA battery. The coil's primary measures 1.2 ohms. The circuit uses 10mA. I am going to charge it with a 5W solar panel that has almost perfect solar exposure.

1.2 ohms = 10 amps @ 12V = 120 watts.
The circuit activates the coil every 3 seconds. This means 28,800 zaps per day.
The pulse length is 6mS X 28,800 = 172 seconds of on time per day, or .048 hours per day.
120 watts X .048 = 5.76 wH / day
10mA = 2.88 wH/day + 5.76 wH/day = 8.64wH/day total. Assuming 30% charging inefficiency, 11.23 wH/day.
7aH @ 12V = 84wH/day, so in theory 7.4 days of battery life.

Seems to me that should work out fine and have decent battery life. I will be using a simple LM317 adjustable regualtor for a charger. Since I am not using a "real" charger, what voltage should I set it at? 13.8? A little higher?

Thanks!

Jonathan
Title: Re: Electric Fence Zapper
Post by: ghurd on November 28, 2012, 11:07:10 pm
I would use 13.8V.

If your circuit math is right, the 5W panel should keep up just fine.

Might want an LVD on it in case a shocked bear knocks in down.
G-
Title: Re: Electric Fence Zapper
Post by: Norm on November 28, 2012, 11:17:18 pm
to test it hook up to a cattle prod and wait for a bear to come 'round?
leap of faith !    LOL !
Norm ;)
Title: Re: Electric Fence Zapper
Post by: madlabs on November 29, 2012, 09:56:18 am
Ghurd, by LVD do you mean low voltage dropout? If so, gotta simple circuit? I am just putting together the art for the final PCB to include the charger and so could add some stuff. Although I am tempted toi make a sub board since the zapper PCB turned out so nice.

Norm, you're the one with the lightning bolt on your picture, YOU test this thing! :)

Thanks, Jonathan
Title: Re: Electric Fence Zapper
Post by: bj on November 29, 2012, 06:27:17 pm
One inch spark?  I'll be standing in the coward's line.
Title: Re: Electric Fence Zapper
Post by: philb on November 29, 2012, 08:28:13 pm
A CRC book of Chemistry and Physics has a good spark table that can tell you how much voltage it takes for a 1 inch spark. 10 mA is a very hot fence charger. Most of the professional chargers are significantly less.

I would guess it is enough voltage to p**s a bear off bad enough I wouldn't want to be in the same county.

If you use a smooth wire to carry the voltage, you may want to wrap it around barbed wire or something pointed to get through the bear's fur.

I had a "Super Safe Leakage Tester" to check distributor caps, coils and wiring for cracks. It was made in the '60's. You could hold your finger an inch from insulation on the test leads and see a blue spark. It was almost all voltage and no amps so no shock. The other settings would drop the voltage and raise the amps. That would make anyone holler and end up on their knees. I never could understand why it said super safe.  :o
Title: Re: Electric Fence Zapper
Post by: oztules on November 30, 2012, 04:36:58 am
Don't ever consider using barbed wire with an electric fence.... it is very very illegal, and downright dangerous.

Having said that, I have delved into ignition coil fencing units before, and can say they do work to some extent.
If your fence is clean, and short (around a haystack etc) they are fine.

If you wish to do any good with a loaded fence, they are useless.

It is far better to build a tiny multivibrator to change the 12v to 400-600 volts, store that in a capacitor and then discharge that into a low impedance transformer.

The ignition coils solution is a very very high impedance solution, and mostly unsatisfactory for most uses..... thats why no commercial solutions use them.

If you want a circuit for this I can provide a simple very effective board design for you. It can do up 10000 volts at 40 amps... good for a 70km- 100km of wire fence.

You will need a small ferrite transformer, and a microwave transformer core or any other reasonable sized core, and wind your own transformers.


Using this system, you can store the charge from the small multivibrator into a capacitor, and then discharge it into a decent core to develop  lots of watts for a small time period..... less then 10/millionth of a second or so....... its a bull stopper.

I have seen up to 400000 watts from this design.... it is simple and very cheap.


DONT US BARBED WIRE EVER!!!! with an electric fence...... getting caught /tangled on a hot barbed wire fence is deadly to some people with iffy hearts and can easily kill a cow in this instance.

No one uses high tension coils anymore, they are next to useless because of the tiny current they produce. Any fence load (grass etc) will knock it down very quickly. A low impedance solution burns the grass (kill not burn ) off the fence.

A 15ma solution will totally wipe out an igntion coil solution...... plus the unloaded voltage is illegal as it will be in the 20000v region... 10000 is the limit here and NewZealand.... I assume it is there too.



..................oztules
Title: Re: Electric Fence Zapper
Post by: madlabs on November 30, 2012, 09:46:59 am
Oz, Phil, All,

Turns out I musta done something wrong measuring the current draw of the circuit. It actually draws less than 1mA except for the LED blink. Tough to determine voltage from distance unless you have a proper spark gap with spheres. As to bears, luckily I live in northern CA where all we have is small black bears not known for attacking people. But they are known for climbing apple trees and destroying them.

The fence is quite short, only around 700 feet. I actually do have mains (inverter) power out there. Oz, I'm quite interested in your circuit and board. By any chance do you use Eagle? If not, even a jpeg would do. Or I can use your art to make an Eagle version. I have no problem doing some xfrmr winding. Out of curiousity, how many wraps of what gauge?

Thanks!

Jonathan
Title: Re: Electric Fence Zapper
Post by: oztules on November 30, 2012, 02:04:25 pm
Jonathan,
12vdc is fine, 240ac volts is fine, 110ac volts is not fine, and would need a little step up transformer to get to the higher voltages needed for storage..... a step up will use some extra magnetising current, but apart from that no change.

I use two boards, one for 12vdc, and another for 240vac. The ac one uses a simple voltage doubler/rectifier to get the 640 volts, the 12v uses single transistor with small ferrite to make the 600v+

When we store this in a capacitor, we can get the energy from 1/2 C (in farads)xV (volts)^2.. 1/2 capxvoltage squared.

We then use a simple diac discharge circuit into an scr/triac... so as the charge voltage rises, we use a sample to trigger the diac at say 600v, and this discharges all that energy into a core.

The tiny ferrite I use is an e49 core, with about two lots of 18 turns of 1mm wire for the primary. One winding for the feedback to make it silly simple, the other primary as the switched primary. The secondary can be 400 turns of spiderweb, as it is small current high voltage.

The power transformer I use are the microwave ones... free so cheap I suggest.

When you dump up to 60 joules into a core (even a 1kw core) it will saturate to hell, but it does not matter for this one shot system.

It consists of 9 turns 2 in hand 1.8mm to 2mm wire (about #12 or #13 AWG) for the primary, and about 200-260 turns for the secondary, I use 1mm wire for that.

The transformer can be just welded/epoxied back  together as it was originally for the microwave duty, don't need to do the I E thing.


The power transformer needs to be neatly  ( side by side wire) wound with each layer separated by motor/transformer paper. This will give us reasonable isolation between each layer and stop the enamel from trying to keep isolation between each layer, the paper does that. We need to leave 3/16th inch of paper over/past each winding layer for the same reason.

It's simple, easy, and very effective technique for very high voltage transformers...... then epoxy the transformer too keep moisture out and you have a very commercial grade fencer for a 5-20 dollars instead of a thousand dollars.

I will do an article for you if you wish. The circuit board is done with protel, never liked eagle.

Try to get picture or gif of unit and board today, maybe article in a few days.


................oztules


A tiny 15ma fencer can use as little as a few uf capacitor into a small transformer for light fencing, and same circuit into a 100-200uf capacitor with a bigger core will get you up into the hundreds of thousands of watts, and draw over an amp..... this will light up a many many tens of miles fence, burn off the grass, andstill pull over 8000v @ 30 - 40 ampsinto a 300 ohm(heavy) fence...... same board and circuit etc.
Title: Re: Electric Fence Zapper
Post by: Wolvenar on November 30, 2012, 03:28:54 pm
At a friends place I setup a store bought fencer on a bird feeder post in an attempt to scare off a repeat offender bear raiding it.
I set a pipe in concrete within a couple pvc pipe/concrete layers.

I don't remember the specs of this fencer but I do know it worked.
To set this up you have to know this fird feeder is on the edge of a retaining wall.
When I replaced the feeder I made it high enough that the feeder itself could not be reached by the bear on its hind legs.

When the bear came for his nightly raid he noticed he couldnt just reach the feeder.
He touched the pole with his paw and was rather surprised, recoiled looked around then decided to rear up on hind legs to push the pole down since he could not reach the feeder any more.

Well I wish I had it on video. He pushed into the pole got zapped then fell completely into it like he lost control of his balance, face first into the pole and off the side of the 4' retaining wall.

That bear got up and ran like hell away, never looking back.
He still sticks around the area but wont come even close to the house anymore.

I don't have a lot of images of this I guess but.
The inside pipe, the other 1' pvc was placed in cement in the ground and this placed in it, and more cement.
(http://gallery.anotherpower.com/main.php?g2_view=core.DownloadItem&g2_itemId=21462&g2_serialNumber=2)

A shot of the retaining wall, but not a good one to show its height.
Before the new setup.
(http://gallery.anotherpower.com/main.php?g2_view=core.DownloadItem&g2_itemId=21468&g2_serialNumber=2)

This had a feeder with a zapper to keep squirrels off.
The bear had taken this down earlier and broke a few perches.
I had to fix that as well as a few places squirrels chewed.
They took immediate advantage of the fact it was down and they could get to it in ways they wouldn't get zapped
(http://gallery.anotherpower.com/main.php?g2_view=core.DownloadItem&g2_itemId=21471&g2_serialNumber=2)

So in this case a fencer deterred a good sized bear rather well.
Title: Re: Electric Fence Zapper
Post by: oztules on November 30, 2012, 06:39:03 pm
Here is a screen shot of the board to show how simple it can be, will do more on this for you later

[attachimg=1]

I like to fill in the board with as much copper as I can...... saves on ferric chloride :)

Here are both the 240v version and the 12v version

[attach=2]

[attach=3]

The capacitor (storage ) is external to the board, as the 50uf 600vac caps are rather large.
The smaller brown caps on the board are for wave shaping in conjunction with the inductor you can see.

The white capacitor on the 240v board is used for doubling and current limiting for when the scr's short the source and cap out direct to the big transformer ... also located remotely..


...................oztules
Title: Re: Electric Fence Zapper
Post by: madlabs on December 01, 2012, 11:56:46 am
Oz,

That looks perfect! I'll do the 12V version as I only have (and will only have) 120VAC in the orchard and already have the small solar panel and so on. The boards in the picture are well within my in house capabilities and I bet I have most of the components kicking around, I have lots of orange drop caps and so on. Do you have a BOM so I can poke around and see what I need? The oven xfrmr looks like the newer, smaller kind, which is good because they are easier to get. A quick trip to the dump will provide one. I have some large older ones but they have been modified for silly high voltage projects and I'd like to hang on to 'em for that.

Does Protel have a freeware version? I'll look into that. I'm not married to Eagle.

Thanks a ton for the help, I think this will be much better tahn my ignition coil model. Although now I'm going to have to find something entertaining to do with it since I made such a nice board and it does toss a nice hot spark. Now who or what can I zap with it... (starts thinking evil thoughts....)

Jonathan
Title: Re: Electric Fence Zapper
Post by: oztules on December 01, 2012, 03:08:40 pm
Sadly, thats not the oven transformer..... thats only the etd 49 step up transformer...
the oven transformer is heavy and as big or bigger than the board... yes a normal microwave tranny...Will get a pic of one converted for you today.

Circuits are not my thing, I make one up while drawing the board, then make a board, then modify the board a few times and throw away the circuit and make the changes from the prototype board .... just bad habits I guess.... the circuit original gets changed so much, it seems not worth remembering in most cases.

I will redo the board so that it is clear what the parts are.

You will note the 240v version does not have the step up, but still needs the power transformer for both current dumping, and galvanic isolation from the mains.

Yes the boards are simple, as is the entire circuit..

I will explain each part and what it does etc a little later today or tomorrow.

suffice to say    oscillator ( about 5 parts inc tranny) goes to rectifier (2 diodes) a damper circuit (resistor and another diode) to a big capacitor in my case (small in your case). About half a dozen parts in the voltage divider for the diac trigger (only because the voltage (600v) is high, so we need a few resistors in series to stop arcing ). Next is the triac bundle (much cheaper than 50 or 100 amp 1000v scr's), a ferrite ring and a few turns of wire, and two 2uf capacitors for wave form smoothing..... and thats it but for the power tranny.

For your purposes, a small power tranny will do, and probably only one or so triacs, and a small cap.

You will only ever get milliamps and spark from an ignition coil, you can gets tens of amps and thousands of volts from the low impedance version.... more power, just bigger caps and transformer..... down side is nothing is for nothing, if you want hundreds of thousands of output watts, it will cost some more current, bigger solar panel.... but  for what you want, you will bluff anything about the place for 10-20ma... good for 5 kms or more....bigger tranny and caps... then 75kms or more circuit remains nearly the same.

I found the ignition coils ones were only good for temporary  haystack protection, or  small temporary fences with no leakage (as they were temporary, and no time for grass to grow into them).... but for a real life fence, they are rubbish.... they just don't have the current to go on with their impressive open circuit sparks.



.....................oztules

Edit:
A download for protel for windows is here:

http://webcache.googleusercontent.com/search?hl=en-AU&biw=&bih=&q=cache:x2gyaH8_c6sJ:http://www.pcb-pool.com/ppuk/service_downloads.html%2Bfree+download+protel+for+windows+1.5&gbv=2&gs_l=heirloom-hp.1.5.0i30l2j0i8j0i8i30l4.3951.14742.0.25130.35.34.1.0.0.0.1378.8480.9j12j5j3j1j3j0j1.34.0...0.0...1c.1.k69TSHudPxM&ct=clnk

It is a demo only, so won't save files, but other than that seems to work.
Use download #123, #124 near page bottom, and it should unzip and install. needs both "disks"/downloads.

PM me for more useful information/download on protel for windows ::) if you get my drift... re saving files etc.
Title: Re: Electric Fence Zapper
Post by: madlabs on December 02, 2012, 11:49:32 am
Drat. That version won't work with my version of windows, which is Vista. And Tuesday I get a new machine that will be running Win8. Oh well, Eagle aint too bad.

Looking forward to the schematic though. Thanks Oz.

Jonathan
Title: Re: Electric Fence Zapper
Post by: Wolvenar on December 02, 2012, 12:25:16 pm
Oh man.. feel sorry for ya, one bad OS to an even worse one.
Title: Re: Electric Fence Zapper
Post by: oztules on December 02, 2012, 02:09:33 pm
Been busy, so will be later.... I use linux, so this runs under wine emulating windows.
I'm surprised your windows can't run it under properties, and then what version of windows to drive it as.... but I don't use windows, so I haven't tested it  either.

There is a free evaluation of the latest version here   http://live.altium.com/#software
Altium is a name change from protel..... at over 5 grand.... gee it's cheap isn't it......but the trial is 30 days, and is free. Don't know how big it is.

If you get on the net and search for "protel 99se download",  you will come up with something as well. There will be some unsavoury sites with cracks as well I suspect ;D


...................oztules
Title: Re: Electric Fence Zapper
Post by: MadScientist267 on December 02, 2012, 04:00:15 pm
Oh man.. feel sorry for ya, one bad OS to an even worse one.

LOL  ;D 

I can only imagine...

No seriously, I can ONLY imagine.  :P

Steve

Title: Re: Electric Fence Zapper
Post by: oztules on December 02, 2012, 04:53:36 pm
Ok,
I have scribbled out a quick circuit that should be right.... :o

[attachimg=1]

The oscillator can be anything you chose if you don't want to wind a feedback style transformer, but I  find it is bullet proof and rugged., mine use larger transistors, (up to tip31 etc) and can draw an amp or so.... it is completely flexible in this circuit.... it just has to oscillate, and make the current you need for the storage you want in the time constant you choose.... I generally go for 1 second pulses... but more is fine, less may be illegal for your country (it is here).

The 640R and the 2k2 can be changed to suit your current requirements, as can the npn transistor. For your project it could be a TO92 size, drawing only a few ma to an amp or so.

The 50uf cap is about the smallest I use for larger fences, but for your size, even 2-4 uf will be fine, and this will allow your current from the oscillator to be small, (TO92 and higher values for the resistor bridge etc.)

Note the start and finish of the windings in this transformer..... otherwise it won't oscillate. (the dots are the starts).

We then rectify  the secondary, and it drives the capacitor. It should be that it takes about a second to drive the caps voltage up to around 500-600 volts.

We then use the 1m 1m 1m 330k divider to get a sample of the voltage, the variable resistor is just to get the timing better, and the finish trigger voltage more precise, but is unnecessary really. The .7uf capacitor is just to load the divider, and  so also controls the timing. If this is too big, the real (big)  cap voltage will possibly overshoot, as the voltage is not a true reflection of whats happening to the main cap, it is slightly retarded, but stops false triggers.

When the voltage across the .7uf gets to the breakdown of the diac, it triggers the triac/s.

The triacs short the storage capacitor across the transformer primary, which for me is about 9 turn 2 in hand of 1.8mm wire. This presents a very heavy low impedance load on the cap and triacs. It is this impedance that will dictate the pulse width and shape. I use about  20 turns around a ferrite, or whatever takes your fancy to impede this current flow some, and so widen the pulse. This helps in transmission over long distances, as the spike is not so high, and a bit broader, it also suppresses RF  Interferance... which over here is no bother.

It also helps keep the avalanche currents down a bit in the triacs. I used to use very expensive scr or triacs of the 50 to 100 amp range at 1200-1500volts, but found a bank of 20 cent traics of the 800v 16 amp variety to be every bit as good..... if you have a bit of inductance in the line ( the 20 turns etc).

This impedance lowers the output voltage by a good deal, but the two 2uf capacitors across the transformer fixes this up (smaller for you), and actually improves it a touch.
The diodes on the tranny are just to stop the back emf from the coil, which is necessarily savage. They need to have a 1000v rating and good surge current for big systems, and not that exciting for smaller units.

The main output transformer for me is a microwave rewound, you may find for your small fencer a normal power transformer with 110v:10v windings will do.. if it can be stopped from internally breaking down...other wise wind your own around any core you can get hold of.

In truth, you can wind it around just the "I" of a big transformer... ie an open inductor, and it will work just as well. The transformers are driven so deeply into saturation, that most of the core is seen as air gap anyway ;D .... so using air instead of the rest of the "E"'s will make very little difference in practice.

Questions or comments?


...............oztules
Title: Re: Electric Fence Zapper
Post by: Janne on December 02, 2012, 06:00:59 pm
Oztules' schematic looks pretty much (in principle) like the commercial zappers I've tinkered with. Only think I might add, is that the ones I fixed always had a bank of MOV's on the secondary side, to eat the energy pulse in case nothing was touching the fence. Not sure if that's really important in practice.
Title: Re: Electric Fence Zapper
Post by: oztules on December 02, 2012, 10:36:24 pm
Yes, without the inductor and capacitors on the primary, the spikes can be pretty impressive.

With the inductor and the caps, it makes the waveform a tiny bit more reasonable, and the rate of change of the voltage spike is slower, and so the transformer behaves a bit more like a transformer, and less like an ignition coil..... so the story goes.

In previous years, the voltage max for this country was only 5000v, and then you did have to protect the unloaded value to stay under the limit and still intimidate the cows, now that has been raised to 10000, it is not so hard to limit to less then 10000v without a string of mov on the outputs, and still have a good loaded working voltage of around the 6000v mark....... one more advantage of low impedance fencers with big (physically) out put transformers with thick wire.

Most (big ones) now have output sampling, to throttle back the output, and don't need mov's to hold them back if they are going to push the limits a bit.


Depends how sexy you want to be I guess.

I have taken to using MOV across the output triacs and the damping diodes, and even the cap.... just in case I lost the transformer, as the oscillator voltage can go very high (>1000v), and this could wreck the triacs etc.... but now I use the cheapies, I'm not so concerned..... and it seems not to have happened anyway.... still mostly use them anyway now... I have a bag full to get rid of.



..................oztules
Title: Re: Electric Fence Zapper
Post by: MadScientist267 on December 03, 2012, 04:29:44 am
I have a couple quick questions about this thing...

You mention tens of amps @ thousands of volts... How is this happening? I get the GIGO thing happening with the output transformer, but you're talking thousands of amps being dumped by the triacs into the primary from some caps that are in the 50uF range, give or take. What gives? Can they really supply all that, even if it is in a zillionth of a second?

The other is, 10kV @ double digit currents... How is this just a warning shot and not straight up lethal to it's victim? There's little doubt that at those voltages,  flesh approaches good conductor status, and so the current would most certainly flow. One can't help but wonder then... Is it skin effect from the pulse being so short?

Oh, and in the schematic, you show a PNP... text calls for an NPN... I'm inclined to believe that the circuit uses an NPN for the simple idea that negative ground isn't conducive to PNP operation when the emitter is on the negative side. Just figured I would mention it... I could be missing something I suppose. :)

Very nice device and layout once I got deep enough into it to wrap my whole head around it.

Steve
Title: Re: Electric Fence Zapper
Post by: oztules on December 03, 2012, 09:34:05 am
Yes it's true... hard to believe, but true.
I use the Gallagher fence tester ( as does most of the world I guess), and it only specs up to 14000v and 35amps.
I'm sure when I have had it maxed out at 40A, it was a bit more than 40A (it actually tops out at 40A)

http://www.gallagher.com.au/common/download.dam.document.aspx?docid=23381&filename=3C2539-SmartFix-in-volt-meter-mode-User-Manual&internal=true&extn=.pdf

I'm afraid with the low impedance fencers, these figures are not unusual...
A "normal" fence on a farm will be around the 6000v@25A under reasonable load (grass load), this would probably be a 200-300 ohm fence. With wet weather, this may climb up to 35-40 amps at a lower voltage... depending on the out put impedance.... it may drop to 4000v even..

It is simply a matter of TIME that the energy is expended in. If you can provide a good enough low impedance (true zero) path to get the time down to infinitely small, the power is infinitely large for any energy at all.... and everywhere in between.  At the discharge times were talking about (10^-7 to 10^-6 for one pulse) your up in the MHZ range .....and thats before the harmonics start....
So
"One can't help but wonder then... Is it skin effect from the pulse being so short?"............ I think so too.

Both for the power produced, and the damage inflicted on the animal. If you keep the pulse very small, the nervous system won't see it as lethal for a one off (skin effect helps here), hence the government rules.  However, multiple hits can still result in disorientation and even death  if trapped for a decent period... that why barbed wire is ILLEGAL in any form with any electric fence, and why there must be at least a second between pulses so you can get the hell out of trouble.

Yes, if you look at the transistor it should be an  NPN.... the feeble 5 min circuit indicates otherwise... probably a hanging offence over there, here I tend to always get it wrong.... I keep thinking it denotes electron flow in the real world, but it is in the conventional current world that dictates the arrow direction.... and I will never ever get used to conventional current. Why we still use a convention where the electrons/current flows from positive to negative bewilders me.....maybe thats why I'm the village idiot.

Even though it is a single DC pulse, it acts like AC in it's propagation too, including nodal points along the fence where the voltage at the end and in places in between, will show higher potential than the source. The inductance and capacitance of the fence all play a part too.

Or you can just hook it up and measure what happens.... I'm not smart enough to be able to guess the nodes and behaviour to any useful degree.



..................oztules
Title: Re: Electric Fence Zapper
Post by: madlabs on December 03, 2012, 10:35:21 am
Yeah, outta the frying pan and into the fire, going from vista to 8. Not looking forward to it. Bummer is that laptops can be tough to stuff an older OS into but if 8 is bad we'll see.

Oz, schematic looks good. NPN/PNP error noted. I'm off for my 2 day shift so I can't play with things but I can read the forums.

I really appreciate the effort! If you are ever in Albion about 5 years from now (when my trees should be producing fruit) I'll buy ya a glass of hard cider! ;-0

Jonathan
Title: Re: Electric Fence Zapper
Post by: MadScientist267 on December 03, 2012, 11:45:49 pm
Interesting...

I guess it's best then that I never went on with my ignition coil system for cars... Not for the engine, but for the idiot trying to steal my stereo...

I used a capacitive coupling to the ground, or should I say attempted... It never did couple well (for reasons I wouldn't understand until much later in life)... But it would zap the $#!+ out of you if it was parked in grass haha

I would be willing to bet the whole thing was highly illegal, and having tested it myself, I can see why. There was speculation even back then as to whether or not it was a "good idea" haha

My answer to that was "Stay away from my car and you never have to find out" :)

If I would have built something like what you have here, I'd be sending this response (somehow) from prison thanks to a most certainly impending manslaughter charge.

The stereo was a "curiosity" to say the least, but that's another thread entirely...  8)

Steve
Title: Re: Electric Fence Zapper
Post by: madlabs on December 06, 2012, 10:28:33 am
Oz, All,

Gotta start the *ugh* transfer over to new laptop and then I have a couple of days worth of storm damage to deal with and a car that got water under the hood and won't start. Hopefully should be able to get to starting the new zapper this weekend. Looks like I have or can salvage everything I need for it. My 5 watt panels arrived, packed crappily but intact. They look pretty good, quality wise.

Title: Re: Electric Fence Zapper
Post by: zartoop on February 16, 2013, 06:03:24 pm
Oztules thanks for all the great info and experience. I hope you can help me a little more with this please.

I want a system that WILL burn vegetation. I am using this on a private building to keep wall creeper under control around windows, doors and eaves.

I can either have two wires (+ve and -ve) or one wire with earth stake.

My test setup is two wires 2500mm long and spaced 25mm fixed to a brick wall. When creeper has grown between the wires the resistance is about 12K. With no vegetation between the wires it is open circuit. I have not measured the resistance of each wire to earth.

Turning one wire into a "hot wire cutter" works but the power required is impractical for a whole building as it needs about 300w just for one wire 2500 long.

I have done quite a couple of tests with various setups but none have done the job. All testing has been with 2 wires and when grown over. I have not done any tests "as the creeper grows" as the systems I have tested are too dangerous to leave on all the time.

Tests done
Flyback transformer. Arcs over in air at 10mm and pulls 20mm sparks on the bench. Driven at 20kHz / 90% duty cycle 12v primary. Will not burn vegetation when grown over. Too little current I suspect and transformer type does not handle loading?
Neon sign transformer.
10000v 30ma. Will not burn vegetation when grown over (12K). Too little power?
Hot wire
Works fine but impractical.
MOT
Haven't been game to try this as yet:)

I would like to try a Weedchopper/Weedburner type electric fence but can't find any circuits. Apparently the old Weedburner type fences were classed as 'high impedance' but this seems in contradiction to some of your previous posts.

Anyway ... Do you have any recommendations / advice please?
Title: Re: Electric Fence Zapper
Post by: oztules on February 16, 2013, 06:41:38 pm
1 wire and an earth stake will do fine.

Just the simple circuit I have given here will easily do what you want.

If you want a 110v or 240 volt system, you will need to just use a doubler for the 240v unit, and a small step up for the 110v, or quadrupler circuit to get up in the 500-600 volt arena.

The only thing that you need to look at is the trigger as shown and explained, .... if you store charge into a big electro, and discharge it into a low impedance transformer, your gonna do some damage to some plants... for sure.

That one shown will burn grass off a 30km fence.

There is no magic, just simple physics.

If you have specific questions i will try to help.

..............oztules

Title: Re: Electric Fence Zapper
Post by: David HK on February 18, 2013, 06:05:08 pm
Fed up with ring neck doves crapping on my BBQ table which is immediately below a mango tree.

I am planning to install a wooden pole horizontally in the tree roughly where the doves like to perch. The pole will be fitted with two x bare 1.6mm copper wires about 12 mm apart. One wire will go to battery ground and the other to my home made car ignition coil type electric fence machine HT output.

In theory the doves will stand on the pole and their feet should short circuit the HT and Grd wire. The resultant effect should be Mach 4.8 doves VTOL and a couple of feathers.

Can anyone see any technical problems with this?

David in HK
Title: Re: Electric Fence Zapper
Post by: DBCollen on February 18, 2013, 06:59:37 pm
be much neater to see them burst into flames when they land
Title: Re: Electric Fence Zapper
Post by: David HK on April 03, 2013, 03:10:37 am
Oztules,

I am interested in your circuit but the one shown above is hard to read. I have spent an hour trying to redraw and name it. Could you please take a look at the drawing and note up any details I have missed or got wrong. Thank you.

Regards,

Dave in HK
Title: Re: Electric Fence Zapper
Post by: rossw on April 03, 2013, 04:49:33 am
I am interested in your circuit but the one shown above is hard to read. I have spent an hour trying to redraw and name it. Could you please take a look at the drawing and note up any details I have missed or got wrong. Thank you.

Hi David!

I'm sure OZ will reply, and I didn't see the original circuit, but immediately the arrangement around the triac and diac looks wrong to me. Also I suspect L1 is actually part of T1. I'm surprised by the arrangement of D2 and D3 - but its not beyond the bounds of possibility. T2 doesn't have the number of turns specified for the primary. What is C5? Drawn as a variable capacitor, but not making a lot of sense to me in the circuit as shown.

Cheers,
RossW
Title: Re: Electric Fence Zapper
Post by: David HK on April 03, 2013, 05:38:48 am
Ross,

The previous page, entry #17 shows the drawing. Its hand sketched and difficult to read, hence my attempt to put some shape into it.

I have numbered all the parts and it would be useful to add all the component values, voltage, uf, capacitance, types etc. Also the coil turns and wire diameter.

I hope Oztules can find a few minutes to spare.

Regards,

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 03, 2013, 05:05:24 pm
After a good nights sleep and morning tea and biscuits I have managed to read back through this topic and as a result parts of the drawing have been updated. The triac and diac arrangement have been revised. Previous C5 has become R8. Am still needing component values, type, etc and above all coil wire diameters and any info on coil winding.


Dave in HK
Title: Re: Electric Fence Zapper
Post by: rossw on April 03, 2013, 05:17:31 pm
After a good nights sleep and morning tea and biscuits I have managed to read back through this topic and as a result parts of the drawing have been updated. The triac and diac arrangement have been revised. Previous C5 has become R8. Am still needing component values, type, etc and above all coil wire diameters and any info on coil winding.

Looks a lot better, David.

I found the sketch you mentioned, and there is definately a circle joining L1/T1, so I think it would help comprehension of the diagram if you called it T1 instead of L1, and even better if you could draw it WITH T1. A common way to draw that is to extend the two vertical lines (the core) down, and put the winding directly under your "primary" to the left of the extended core. In reality, "L1" as it is currently drawn is the primary winding. What is on the left side of T1 is the feedback winding and on the right is the output/secondary.

You should join the wiper of R8 to one side or the other. At the moment, R8 is a fixed resistor (or a pot being used as a fixed resistor)

RossW
Title: Re: Electric Fence Zapper
Post by: David HK on April 03, 2013, 06:01:57 pm
Is this what you mean? I still have to update various text for a couple of items.





Dave
Title: Re: Electric Fence Zapper
Post by: rossw on April 03, 2013, 06:09:40 pm
Is this what you mean? I still have to update various text for a couple of items.

Very nearly, yes. The bottom two coils are a seperate transformer, so shouldn't be shown on the same core... so right idea, just carried too far :)
Title: Re: Electric Fence Zapper
Post by: David HK on April 03, 2013, 06:37:57 pm
I think this is very close. Is the toroid coil correct?  I need to know the diameter and wire size.

There are some photographs on another page which show 240AC and +12 DC units.

I can see the ETD 49 coil arrangement, but where is the final transformer coil for the fence connection?

Dave


Title: Re: Electric Fence Zapper
Post by: David HK on April 03, 2013, 07:10:29 pm
Ross,

After reading the thread again I have reached the following conclusion:-

the 50 uf 600  volt AC capacitor is off the board (PCB), as is,

the final power transformer for the fence which is made from a microwave transformer.

If this is correct that answer a few more questions.

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on April 03, 2013, 11:43:33 pm
Ross,

After reading the thread again I have reached the following conclusion:-

the 50 uf 600  volt AC capacitor is off the board (PCB), as is,

the final power transformer for the fence which is made from a microwave transformer.

If this is correct that answer a few more questions.

I picked the low-growing fruit - the stuff I could easily see or deduce from the diagrams and experience.
Exactly what Oz made and how he made it really needs to wait for his input :)
Title: Re: Electric Fence Zapper
Post by: madlabs on April 04, 2013, 10:14:57 am
Been a while, I got sidetracked while installing 1.4kW more panels and getting all the fruit trees planted and the fence finished. Now it's time to get into the fence zapper.

Looks to me from re-reading the thread that the xfrmr on the left is the ferrite core and the output one is the MOT. Going to go dig around and see what I have, most of my stuff is older iron core so I might have to *gasp* buy one.

Jonathan
Title: Re: Electric Fence Zapper
Post by: madlabs on April 04, 2013, 11:10:15 am
Drat, no MOTS that I can find, I must have scrapped 'em when I moved. Can't believe I did but I can't seem to find any.

As to the input xfrmr, think a  CRT flyback core would work? That's all I can find in ferrite except toroids.

Sigh. Rainy day and not enough parts on hand to play. Maybe I'll go take one more dig.

JOnathan
Title: Re: Electric Fence Zapper
Post by: David HK on April 04, 2013, 07:08:37 pm
Friday 5th April 2013

Translating the circuit sketch and slowly working it out is taking quite some time.

Nevertheless, I am getting there.

Some things I need answers for:-

What is the value of the variable resistor R8?

Is the Power transformer (ex microwave off board?

Is the Capacitor C1 50uf 600v AC off board?

I need a complete update on all coil winding turns and the diameter of the wire.

I have the feeling (rightly or wrongly) that the EDT49 coil unit may be too big for the board. Is this a wrong assumption?

The drawing has been updated to show the triacs in parallel, the toroid, and a TIP 31 to replace the 2426 transistor.

So far so good.






Dave in HK
Title: Re: Electric Fence Zapper
Post by: oztules on April 04, 2013, 07:24:17 pm
Sorry folks, been busy making a solar pump controller board... maybe post that soon, and get David to do the circuit for it.... I'm hopeless, mine are disjointed scribbles on bit s of paper, and I end up designing  it on the board... just  a backward hic................what do you expect from a village idiot...

Anyway.
The ferrite is two primary winding . The primary as I wind it is just 2 in hand 24T ( or 18Tt or whatever completes a single layer for the wire I have at hand on the day) turns... so both 24 turns, and use 1 of the 2in hand for each primary... making 2 single primaries of 24T ( or 18 or whatever fits for 1 layer of the core). I use 1mm wire for the primaries.
The secondary of this ferrite tranny is simply about 400-600 turns of fine wire I pinch from the secondary of the original microwave tranny... probably about .5mm wire
NOTE the start and ends of this tranny.

The Big transformer is off board as it weighs about 10 lbs or more.
It is wound from 1.8mm  (#13?) wire for the primary (2 in hand 9 or 10 turns) and about 200 for the secondary 1mm wire will be fine for the secondary.
Don't get too carried away and wind 300 or 400 for extra voltage, the reactance will current limit it probably, so 200-260 turns is sufficient for 10000V and beyond.

Energy storage is 1/2E^2 x C... so voltage is the key to Joules in storage.. more joules, more energy to dump into the output tranny.

The variable resistor... I use 220k... because I had a lot of them left from another project years ago... probably 1M would give you more control if you need it... or just change the resistors in the divider  (1M to something else)

The 50 uf cap is off board in my case, as it is big, and would take up a lot of real estate for no reason.

The torroid can be about 20T of whatever wire you can wind comfortably in small toroids, I find 1.5mmwire is about my winding limit, and commonly use only 1mm wire.. not critical.... It does not need this and the two caps across the primary......., but it helps keep the triacs alive, and the RF down.

Think that covers it.

Well done David, I haven't proof read the circuit, as in a hurry at the moment. will look back later tonight or tomorrow perhaps.

Have fun with it.

............oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 05, 2013, 01:43:33 am
Oztules,

Your last e-mail was most useful and I have incorporated your comments about coils and coil wire sizes onto the schematic.

Can you please help with the following:-

Triac’s      what size and amperage? Any suggestion for a common part number. 
               Voltage and amps.

Diac   As above.

Diode D1 100 volt   any preference 1N????

All resistors    any wattage specification?

Resistors    R4, R5 and R6 what size and wattage?

Resistors    R1 and R2 what is the value and wattage, and should there be an R3 and R4? I’m confused on this part.

Toroid      Can you provide some idea of internal and external diameter, and width.

The schematic seems to embrace everything so if you could peruse it from left to right to add any comments that would be very useful.

Readers should note that the circuit schematic has been drawn with Express Schematic software and I have also produced an Express PCB layout on mini board size. The PCB layout has been checked against the Schematic using the software to highlight all connecting parts. They all match – at the moment.

I have a coil ready for re-winding as the main power coil (ex microwave I think). The last awkward job will be to find an ETD49 bobbin assembly for the remaining Coils 1, 2 and 3.

So far so good, and nearly there.

I am always a little confused with Australian English. I am forever mixing up a tranny with a dunny. I suppose when has been zapped by your tranny one would need a dunny anyway!

Dave in HK
Title: Re: Electric Fence Zapper
Post by: rossw on April 05, 2013, 04:33:20 am
I am always a little confused with Australian English. I am forever mixing up a tranny with a dunny. I suppose when has been zapped by your tranny one would need a dunny anyway!

Be very careful!

Context and company dictates much!

"Tranny" can be a transistor, a transformer, or a transvestite.
A dunny however is always a dunny! (toilet, loo, thunderbox, outhouse, john etc)
Title: Re: Electric Fence Zapper
Post by: madlabs on April 05, 2013, 09:46:29 am
Oz, think a core from a CRT flyback would work? The older style, two "C" shaped, air (paper) gapped? Cuz' I gots one of them.

Jonathan
Title: Re: Electric Fence Zapper
Post by: madlabs on April 05, 2013, 01:49:59 pm
So, I wound the secondary, using AWG 24 magnet wire. I couldn't locate my little coil winder, so I made this sophisticated setup:

[attachimg=1]

The secondary coil bobbin was made from some karropak gasket material rolled into a tube with a couple of insulating washers epoxied on the end. All went well until about the 7th layer, when a combination of cat, coffee and sneezing caused a little uneveness in the coil. Still, it came out OK. By my calculations I should have close to the 600 turn target.

[attachimg=2]

A question about the primary, I assume we are talking about two side-by-side coils, not layered. Also I see 10 turns and 24 turns on top, but in the schematic see two 24 turn coils. I'm going to go ahead and wind 24 turns and leave room for the rest, just so I can test the coil ratio and see if I'm in the ballpark for 600V.

Jonathan
Title: Re: Electric Fence Zapper
Post by: madlabs on April 05, 2013, 03:59:33 pm
Wound a primary with 10 turns and 20 turns of 18 awg wire. I couldn't fit the full 24 turns, so hopefully that will be ok. Must have got the secondary turns in the ball park because 97 mVAC in yields 920mVAC out. I prolly have the stuff laying around to lash up the input side and see if I get around 600VDC out.
Title: Re: Electric Fence Zapper
Post by: oztules on April 05, 2013, 05:37:08 pm
Ok, CRT transformer is fine. If the starts and finishes are correct, the transistor will see positive feedback in the base, and it WILL oscillate.
The turns... I seem to have created confusion with my slack winding practices.

It has two primaries. Both the same turns number. I use 18-24 depends on what wire I have on hand... why?

Simple, I like to wind the first layer so that it runs from one end of the former to the other, close wound... just to keep the layer neat and clean...... but it would take 40 odd turns to achieve a full layer..... so I wind two in hand, and so wind both primaries together. This gives us close coupling, a single flat layer, and I only need to count once, and the starts and finishes are obvious.... so thats why I do it....... I'm a lazy slob.

The secondary is as many turns as you can fit on, but less than 600, or the reactance may well current limit the output, and is a waste of wire to go more.

David.
The free wheel diodes need to be as big as you can get in there.
EDIT: That should be 1000v not 100v.........6A10 are 1000v diodes
I use 6a10 100v 10A diodes X2. They are only 10A but surge is about 800A combined... and on a larger system, should use more or bigger.

Primary of transformer is 24 and 24  ( or 18 and 18 etc) as on the circuit, not as in the inset (24, and 10)

R4,R5,R6 1/2W
R1 2k2 R2 640   1w  for lower power systems,  with bigger transistors for more drive 2W.

Both resistors are very flexible. Want faster charging for larger UF caps, then , go to lower values and bigger transistor..........to lower the power in the circuit and keep the charge rate at 1 second or more for low UF systems, then higher values or smaller transistors.

Toroid..... any toroid from the outputs of the computer power supplies would do. They are materials suited to this purpose, and are freely available.
Size... don't really know, about 32mm outer, 12mm width,and 20mm hole... just a guess from here. They are out in the shed, but just grab em from computer supplies. They are not critical in any way.
The etd49/39 (maybe etd29 may be a bit small for 30uf systems and above), can be any thing you can scavenge from tv sets power pwm cores, or computer monitors etc, or even as Madlabs has done, the old eht cores from older tellies.
 There is nothing critical in any of this except to get the starts and finishes of the little oscillator correct, if so,it should run.... amplifier+ pos feedback=oscillator

The diacs.. no markings, but from memory, about 30 odd volts step off/ avalanche. I bought 100 for $2 inc shipping from your country.
Step off voltage is of no concern if yours are different, as we just need to change the sense circuit (the 3 1m resistors) to suit the the diac... they are the divider after all.

D1 is just a diode to protect from reverse leads.. a 1A diode of anything over 30v will do.

R4-8 and C4 are your sort of timing components. They give you a delayed reaction of what is actually happening with the capacitor V, as well as determining when the step off of the diac occurs.  C4 provides a load for the divider to work into, and stops spikes triggering prematurely, R4,5,6 and 7 provide the divider, and R8 some fine control.


....................oztules


Title: Re: Electric Fence Zapper
Post by: David HK on April 05, 2013, 06:20:45 pm
Oztules,

Many thanks for the update. All points noted. I will assimilate everything into the drawing, including supplementary notes if I can get them in.

I have ordered an ETD 49 from local HK company.

I may (will definitely) come back with an updated drawing. Check back in a day or so to see if I have more questions.

Thank you so far.

David in HK
Title: Re: Electric Fence Zapper
Post by: David HK on April 06, 2013, 01:07:05 am
p.m. Saturday 6th April 2013       

Hello Oztules,

Drawing updated as follows:-

All resistors rated for 1 watt, or, ½ Watt.

All diode type numbers are 6A106A       1,200v x 100A

C2 and C3 specified as 2uf 400v AC (will change spec if wrong)

Method of winding coils 1 and 2 primaries, and 3 as secondary, noted.

All triacs are:-   BTA26-600B   600v  x 25A

A question:-

In Page 1 of this thread, there are some colour photographs at Reply #10. On the 12 volt PCB I can see some light blue items – what are they? Do they feature in the circuit now being drawn?

There are also two brown “Caps” are these the 2uf @ ~ 400v items?

Capacitor C4 @ 0.7uf. Can you offer a voltage for this, or, a product number if known. It looks like a Mylar of some value.

That’s about it for today.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 06, 2013, 02:30:22 am
http://www.ebay.com.au/itm/100-BT137-800E-8A-800V-Philips-Sensitive-Gate-TRIACs-/200530873298?pt=LH_DefaultDomain_0&hash=item2eb0924bd2
I use these, 18 bucks a hundred, 800v 8A for the "scr" ( triacs are cheaper...), but technically it needs only a scr not a bidirectional switch.

The 1200v 150A diodes are way over kill...... 2 or 3 parallel 6a10 would be enough for most folks for the free wheel, they have high surge, and the surge is very very short.

 The rectifier diodes need only be 1n4007 eg http://www.ebay.com.au/itm/100x-IN4007-DO-41-Rectifier-Diode-1A-1000V-1000-Voltage-/120712606542?pt=AU_B_I_Electrical_Test_Equipment&hash=item1c1b08334e  3 dollars per hundred and free shipping.
and use them for the input diode

The blue things were an attempt at stopping spikes>600v MOV (varistor).... sometimes I use them, mostly don't. These things have been remarkably stable out in the field.

The caps for the storage (50uf 450vac) are motor run AC caps  We can get away with the 450vac, as the peak for this is over 600vdc (450X1.414), and we use DC.

The 2uf ones should be the same, but the poly ones @ 400v seem to do alright,as the super low impedance of the primary of the transformer keeps the voltage clamped down low. Never actually measured it with the scope.

The C4 is any cap running over 100v. It really only sees less than 40v before the trigger goes, but a bit of clearance is good.



................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 06, 2013, 03:02:10 am
Thank you Oztules.

Diodes and Triacs changed as per your comments. All available locally. Just one or two items (Cap C4) to check out for local supply and I think when that is updated the schematic will be complete. Will probably post that next week.

Next step see how big the ETD 49 is, and then see what I can do for PCB design.

So far so good.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 06, 2013, 05:51:00 pm
Oztules,

At the age of 65 I am still learning electronics. Some things I easily understand and others I have to learn as I go.

ETD 49 transformer. I have studied this in the Internet and the bobbin width is 32.7 mm wide. This means that a winding of 2 in hand by 1mm diameter wires will only achieve some 16 (32mm) turns rather than the desired 24 turns (48mm). About a 30% shortfall.

It then occurred to me that the objective of 24 turns could be achieved by finding an old  (or newish) laminated steel transformer with a 50 mm wide bobbin to accommodate the required turns. Thereafter the bobbin can be wound for whatever one can get on it but not exceeding size constraint of the laminates.

No doubt there is a performance difference between ferrite and laminated steel, but in this case would it really matter. Your advice would be welcome.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 06, 2013, 11:22:47 pm
Advancing the above logic on a cool Sunday morning and with the help of Excel and a small laminated type transformer I have some new arithmetic.

Rectangular bobbin = (L x B x H) 31.5 mm x 20 mm x 23. Total circumference (2 x 31.5) + (2 x 20) = 103 mm. 

The ETD 49 bobbin is 16.7 mm dia and 32.7 mm wide. At 24 turns of 1 mm wire (one in hand) the length of wire  = 1,259 mm.

12 turns of 1-in hand (1 mm dia) on the rectangular bobbin = 1,236 mm (12 x 103 mm) which is not far off that for the ETD bobbin. 12 turns @ 1 mm is a width of 12 mm. Since the rectangular bobbin is 23 mm wide (or as near as damn it) it will accept 2-in-hand and leave a shortfall of 1 mm.

The only problem is working out how many turns of 0.5 mm wire can be placed over the two primaries.

What a way to spend Sunday morning.

Dave


Title: Re: Electric Fence Zapper
Post by: oztules on April 07, 2013, 12:24:02 am
Golly David,
Your over thinking this. I just get a microwave tranny, and use the primary coil off that for winding the primary of mine, and the secondary wire from the micro for winding the secondary of mine. 1 microwave transformer will wind lots of these little oscillator transformers.

However, you have goaded me into actually measuring one of my formers, and they are in fact 33mm long (internal) by 19mm diameter.
There is a LOT of fexibility here... and it is obvious that my eyeballing the wire and guessing it was about 1mm, was not as close as I had suspected. It must have been somewhere nearer  <.9mm. ( after you unwind it, stretch it to straighten it, I don't know what it started out at, but usually 18 (36) fits the former)

Wind whatever you can get hold of for the layer, and it will do fine.
The ferrite is much better than the iron, as the frequency will vary from low to very high as the charge voltage changes. the iron may interfere with the efficiency of the transformer as it tries to get to the >15khz part of the cycle, and it is in this region it struggles the most.

So, just get the etd49 former, and wind 2 in hand of whatever wire you can get hold of that is close to the .9-1mm size ( I know I have used <.8mm before to just as good a result. The small turns number, and modest current would allow for .5mm wire, and still be fine, but like I said, I just want to fill the first layer from end to end, and be tidy. 18-24 turns gives you some idea of what wire I must have been using out of the old microwaves, and whatever else I can scavenge on this island. ( startermotor relays, normal relays, wire out of the fans in microwave ovens..... you name it I will have tried it)

Your tables don't take into account the stretch that can be applied when you wind it on a 4 ton lathe or big handled coil winder, practical will tell you what really fits.

Remember when making the big transformer, each layer needs to be insulated from the last with transformer paper or equivalent.. to stop arcing.... 10000+ volts like to find a way where it can, but separate layers seems to work fine, then epoxy the transformer when finished.... don't need moisture in it. Over here night dew is almost like a mm of rain.... ocean next door.


...................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 07, 2013, 12:51:56 am
Thanks Oztules,

I have finished, for the time being, the schematic and will put it up for your eagle eye sometime next week.

Your last note was very useful as a guideline. I have a home made coil winder with counter left over from my Hugh Piggot turbine coils so I should be able to adapt that for winding.

Point taken on the ETD 49. Mine should arrive this week so I will let you know how that goes.

I have also picked up an old 220/110 transformer from the local scrapyard so that should keep me occupied for a day or so. It weighs 10.93 lbs.

If you could cast your mind to it, is there a recommended way of testing any part of the control circuit up to the main transformer?

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 07, 2013, 05:09:54 am
Hmmm.... testing....
Tricky..... Without the transformer, you need to be very careful and quick.

Suppose it is all ok, what can we expect to happen?

1. If we connect the 12v we will hear a low pitched squeal rapidly growing to a high pitch squeal... but by the time it gets to high pitch, we may have well over 600v in the big cap.... so...

2. We connect up the 12v by touching the terminal, if we hear the oscillator start and climb, we quickly pull off the 12v wire. Now measure the voltage stored in the capacitor, if you held for 1/2 second, it will probably be over 400volts.. so the oscillator is working..... so how do we test the next bit... the trigger... ( use a resistor to bleed the cap back down to zero)

Well without a load of some type ( low value resistor perhaps) we don't dare try.

With a low impedance load of some type across the output where the transformer would be, we can tickle the input and hear the squeal run up with each tickle.... with a meter across the capacitor, It should get to about 500-600 and then discharge into the resistor.

We can do this by tickling the oscillator, and watching the meter.. if we get up to near 600v, and nothing has happened, then there is a fair chance it is not going to trigger.... almost impossible to see why, as it is so simple... but it gets scary driving it much higher, as the cap is nearing it's limit..... if you want you can put 2 caps in series, and now have 1300v head room to test with, but the oscillator is capable of over 1000v in all likelihood, and can drive the diodes out of business too. The whole thing relies on the trigger using up the voltage, if it is not connected to a load ( transformer primary) then all bets are off unless you have a load.

Things that have gone wrong:

If the freewheel diodes die, they ( mostly) die short, and the oscillator just does a low squeal, and does not rise, it is clamped by the freewheel diode/s  being shorted.

If the rectifier diode/s fail, the thing may develop low voltage 100-200v, and the diodes may fail short, but no always.. fist time I have seen this, usually they always fail short.

If the oscillator fails, then dead.
..
If the main cap fails, then odd behavior, these wound caps can fail all strange. Sometimes ok up to a certain voltage, sometimes no capacitance, sometimes short... So the oscillator will scream to match the fault.... ie rise normally for a bit then stop at that point... cap charges half way, then shorts etc etc.

Never seen a fault in the trigger circuits.

It the triacs have failed, then drop off the transformer, and that removes the load it would have presented to the cap, and so tickle up the voltage, if all well, triac/s failed... usually only 1... closest to the cap.


Hope that helps a bit.


................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 08, 2013, 06:57:15 am
Oztules or any one else with coil winding experience.

I now have the ETD 49 plastic coil former. After doing the mathematics I shall be using 0.8 mm wire for the primaries which will permit 20 turns of 2-in-hand across the width of the coil. This is a halfway house between 18 and 24 tuns and 1 mm dia wire which only permits 16 turns across the bobbin width.

Having done that I intend to wrap that coil(primaries) with thin transformer paper.

The next bit forms my question. This involves the 1 mm dia wire for the secondary. After I have swept a row of 1 mm across the width of the coil do I need to add another transformer paper liner over the wire before commencing with the second row and so on.

Or, do I (say for example), wind a 100 turns and then cover that with transformer paper and each successive 100 turns thereafter until I have completed ~ 500 turns or thereabouts?

Advice would be welcome.

Dave in HK
Title: Re: Electric Fence Zapper
Post by: oztules on April 08, 2013, 04:36:01 pm
David, there won't be room for transformer paper with 1mm wire... secondary should be spider web wire.. .5m etc

I don't use transformer paper on this tranny, as there are plenty of layers separating the start layer from the end layer. Keep the start and end fly leads apart at least 1/4" (Don't cross them in the transformer).

The loaded voltage will always be less then 600v, so it is no real concern... even with recycled wire from the microwave transformers.

Now for some Weird stuff:
For anyone else watching this, I have used a transformer secondary from a micro, only to find that it would not work. There was something strange with the wire... I never found out what. I rewound the same transformer 3 times with the same batch of wire from the same micro, and none of them worked...odd, and can't explain why, next batch of wire from another transformer worked fine as always....... never seen it again, but there must be some voodoo wire out there somewhere.

Just keep it tidy, without letting the next layer slip too deep at the former ends into the last layers, and all should be fine. Never seen one of these transformers fail from anything now I think about it, and there are quite a few out in the elements for the last 4 years or so.

The main transformer is a different story.  High voltage, and very high currents exist here, and each layer needs to be carefully wound, with transformer paper exceeding the layer width by about 5mm each side. This will make it  very hard for the arcing which would occur instantly without this protection.

Commercial formers for this voltage have lots of individual 1/8th" wide sections all side by side, and you fill each "slot" before going to the next, and this separates them for factory winding.

The paper works a treat like this, and does not arc.... but won't last 5 mins without this treatment.


..................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 08, 2013, 05:04:46 pm
Oztules,

Your note above arrived in excellent time for my morning tea and biscuits. My 6.30 am time must be your 8.30 am time.

Everything above studied and noted. Will follow your guidelines. Am doing well on parts  and have all the coil pieces, triacs, diac, and will shop for the toroid this morning. All being well I can put up a few photographs towards the weekend.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 09, 2013, 05:44:53 pm
Oztules,

There is a problem. I spent a few hours last evening tracing the lay out of the circuit as shown in a PCB photo earlier in this thread.

There is a significant circuit difference with the toroid and possibly the diodes as shown in your hand drawn sketch.

I no longer know which one is correct. Drawing below for reference.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 09, 2013, 11:41:53 pm
Both the  drawings are in fact wrong.

The circuit board shows the diodes across the switches, which is fair. This will catch the toroid and transformer back EMF, The hand drawn one has the diodes and caps on the transformer side of the toroid,.. works, but does not kill the back emf from the torroid itself, but better to do what the circuit board does... put the freewheels on the switch side of the toroid, and the caps on the transformer side of the toroid.

Circuit board is right, hand drawn will work, your circuit board drawing of the circuit is back to front, you have the diodes where the caps are and visa versa.
The caps are to shape the primary currrent, so need to be on the primary.
the diodes are there for freewheel chop of back emf... so need to be on the switches.



.............oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 10, 2013, 12:21:00 am
Oztules,

I've noted the above and changed the capacitors and diodes around. Does this now make the circuit a workable proposition?

Is there anything else that you beady eye may have overlooked?

Dave

Title: Re: Electric Fence Zapper
Post by: madlabs on April 11, 2013, 10:54:22 am
Re-wound my primary, wound up with 2X 20 turns. If I need to I'll take some turns off the secondary to bring the volts in line. I have the stuff to build the DC power side. I'll figure out a dump load. I've got some OBIT's (oil burner ignition transformers) or NST's (neon sign transformers) that should work.

Oz, thanks a ton for all of the effort and to David for being schematic guy!

Jonathan
Title: Re: Electric Fence Zapper
Post by: oztules on April 11, 2013, 05:03:10 pm
Just remember Madlabs, the input impedance of the main transformer will dictate the wave form, and the instantaneous power.

The caps discharge into a virtual short circuit with my transformers ( 9-11 turns of 1.8mm wire X 2 is almost zero ohms, and almost zero impedance.

I have tried some normal 240v:12v transformers, they work well for a few minutes until the secondaries fail.

The neon transformer may be ok insulation wise, but the primary may be a  high impedance ( 110v) and the secondary may be .. well ...I can't guess.

Luck with it all.
David has done well, and approaches it with a professional bent.... the same cannot be said of me I'm afraid.



......................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 11, 2013, 05:53:56 pm
Oztules,

Thank goodness you’re back. I thought my incessant quest for detail may have frightened you away. Detail has been part of my everyday life as a staff officer in Hong Kong Police Headquarters until retirement. Miss a point of detail and things can easily go wrong. Get it right and there are gongs for all. Back to business.

I have progressed further and have used my free PCB Schematic and PCB Express software to produce a printed circuit. The layout is provisional until I can get the tails for coils 1, 2 and 3 soldered onto the bobbin pins. Thereafter I can finalize the layout and/or change anything at the last minute.

I am still gathering parts – some are easy and other not so. The hardest is a 50uf 600v capacitor. Hong Kong has plenty of 450v AC 50uf capacitors but higher voltage is difficult. I shall have to pay a visit to the local scrap yards.

The next step is to visit my local ‘lathe man’ and alter the coil winder (ex Hugh Piggott coils) to that I can fit on the ETD 49 bobbin and the same for the main coil unit.

The PCB is straightforward in layout. The very wide tracks are suitable for 6 amps (don’t know what voltage) and I have tried to keep a wide distance between heavy power tracks. The layout is spacious on the basis that removal and replacement of busted parts can be done easily. Hole diameters and the space needed for large components has been altered so that everything fits comfortably. The miniature coils and associated lines shown on the schematic are for circuit checking only, and will be removed later.

If you can spot anything wrong, or suggest an improvement please let me know because there is plenty of time to make changes.

Dave

Title: Re: Electric Fence Zapper
Post by: oztules on April 11, 2013, 11:21:37 pm
"The hardest is a 50uf 600v capacitor. Hong Kong has plenty of 450v AC 50uf capacitors"

Thats a perfect capacitor to use.... 450v ac has peaks of  1.414* 450= 636v peak. every .01 seconds at 50hz........so the cap is quite happy at <600v DC

...................oztules
Edit, have a good look at your toroidal, and tell me how it works??? It is supposed to be in series with the primary of the transformer... not in series with the diodes.
Change one track from the output of the triacs from where it is, to the other side of the toroid... where the anodes of the diodes are at present.
Change the circuit diagram to reflect this change... this bit has been tricky for you from the looks of it.

I did not see the circuit before, as I usually just look at the recent posts... sometimes the pics come up... sometimes they don't in that format....... ( we did discuss this here: "The circuit board shows the diodes across the switches, which is fair. This will catch the toroid and transformer back EMF, The hand drawn one has the diodes and caps on the transformer side of the toroid,.. works, but does not kill the back emf from the torroid itself, but better to do what the circuit board does... put the freewheels on the switch side of the toroid, and the caps on the transformer side of the toroid."
Title: Re: Electric Fence Zapper
Post by: David HK on April 12, 2013, 03:40:06 am
Oztules,

Regarding your last note to change a triac track line.

I understand the anode and cathode of a diode – straightforward – but things need to be a little more clear on which triac track to change. At the moment the last schematic shows:-

the top side of the triacs connecting to one side of the toroid and Capacitors C2 and C3, and,

on the bottom side, the triacs go to ground.

Based on the above two sentences, which one needs to go to the anode side of diodes D5 and D6 on the other side of the toroid?

Once you have clarified this I will update a schematic accordingly.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 12, 2013, 07:49:16 am
The green track from the triac (A1 terminal) goes to the anode of D5 AND 6....not the right side of the toroid
That way the A1 goes through (series with) the toroid to the primary of the output transformer, rather than bypassing it as it is now.


...... oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 12, 2013, 05:10:46 pm
Oztules,

Thanks for the above.  The attached schematic now contains your recommended revision regarding the Triacs connecting to the anodes of the diodes.

I expect your bored stiff with looking at this circuit, but would you mind giving it the once over again for correctness.

I have a question concerning the variable resistor. What current does this carry? And, if it’s fairly large, is an off-board VR required? If Yes, I need to enlarge the holes for wire size.

Next question. You mentioned earlier that the toroid should be in the supply line. Is it worth thinking ahead and adding an alternative layout into the PCB so that with the aid of ‘jumpers’ and alternative positions for the toroid, components can be repositioned? The time and space is available to do this, but could you give me a sketch or sufficient written detail to achieve this.

That’s about it for the moment. I look forward to your comments.


Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 12, 2013, 07:20:23 pm
"Next question. You mentioned earlier that the toroid should be in the supply line. Is it worth thinking ahead and adding an alternative layout into the PCB so that with the aid of ‘jumpers’ and alternative positions for the toroid, components can be repositioned? The time and space is available to do this, but could you give me a sketch or sufficient written detail to achieve this."

...... No.

It is worth you looking at the PCB layout I used. Note how thick I tried to make the power tracks. These will carry tons and tons of amps for a very very short time. Our losses over these can be quite high.
I tried to use as much copper as i could in this section between capacitor and transformer. Even the to220 triacs have wide pin spacing, so the track down the middle is as thick as I could get.... but also I use well over 1/16the inch or more of solder on all the copper tracks involved with the power lines... and embed copper into it as well.

Notice also, the tabs that go to the transformer and the main capacitor on the non-triac side are next to each other on a large land, your have a thin 3" track, when they could have been right next to each other, and so keep noise and transmission loss to near zero.

In short, I think you would do well to redesign the power tracks to use as much of the board as possible, with as much copper as possible, and keep the two in/ou tabs to the cap and transformer on the non-switched channel next to each other.... or if your cap has 4 pins on it's top, you could route the transformer direct to it, and have no board losses on that arm at least.

Yes it will work fine in it's current form, but if you want to push lots of fence, you need to keep the losses in the toroid only, that way you can control  the losses so that you get performance and life out of the triacs.

Very high currents involved in the primary circuit.


..................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 12, 2013, 09:02:30 pm
Oztules,

You’re an excellent teacher and I hope you can put up with me as a student.

Your notes are fully understood. I have taken the opportunity to draw your circuit layout in AutoCad which is where I picked up the difference in your sketch circuit as opposed to what you actually produced and have shown in photograph form further back in this thread.

Only this morning I was looking at the photographs again and I noticed the splayed legs of the triacs. Likewise, I have noted how you keep the “take off’ tabs close together.

The PCB illustration I have produced has been an interesting interlude and it has helped me understand a lot about the circuit layout.

I shall now put my shoulder to the wheel and learn how to use PCB Express and draw power and ground planes. At the ripe old age of 65 I never seem to stop learning these days.

The prospects of me deploying this kit in earnest are slim, but I am enjoying the technical appreciation of it all so that I can at least fire it up in my back yard. I expect other forumites are following this thread with curiosity if nothing else, and it will be interesting to see if Madlabs manages to electrify Canada or wherever.

Keep in touch and I will be back with a new PCB layout in a day or so.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 13, 2013, 04:47:01 am
I'm sorry David,

But I never have a circuit of this final thing or anything else I build ( which is plenty).

It is usually a series of disjointed squiggles of bits of the thing, and it takes it shape on the PCB board itself in the computer. I have never used the schematic capture part of protel software.

So I never really have a circuit, and am too lazy and don't need one once i have gotten the board to work as I want it... just a lazy village idiot. Print more boards if I need them, and just use the pcb program to tell me where the bits go... after a few years I have no idea what I have done, nor how I did it. My memory is very porous in this regard, and I really don't care much about it.

It is a shame really as I do lots of projects that may be of interest, but never have the supporting paperwork, as it has gone to heaven by the time I have finished he project, and usually my initial design changes dramatically from start to finish, as I see better ways to do things. I am no Electronics Engineer by a long long way.... but usually get what I need to get going successfully.

Have fun with it... your never too old.



...................oztules..... just another old coote
Title: Re: Electric Fence Zapper
Post by: David HK on April 13, 2013, 05:30:14 am
Oztules,

Don’t be sorry for anything. I like your hands on style and I think most Forumites are interested in this small project. Chin up and keep going!

You were right! Your PCB design is far superior and quite easy to set up once one has the knack of using the software.

Attached is my first attempt which is less graceful than yours as it lacks the chamfered corners in many places.

A few observations if I may.

I also found it hard to widen the triac legs and have gone as far as I dare in this drawing. It has occurred to me that I can use a series of tube spacers and a long bolt to link all the triac Tabs together and then connect that to the plane containing the toroid and diodes D 5 and D 6.

One item I cannot find in Hong Kong are PCB tab connectors. They are as uncommon as kangaroos swimming between Wilsons Promontory and Flinders Island.

The red lines connecting coils and C1 are temporary for circuit identification.

Any general comments on planes too close to each other or anything else?

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 13, 2013, 09:06:49 am
That looks to tick all the boxes.
I just used a top3 outline for the triacs, and that doubled the realestate, plus making the track very thick in the Z plane (third dimension).

I'm pretty sure I ended up buying the tabs from HongKong from RS components ... 40 dollars /1000.


.................oztules
Title: Re: Electric Fence Zapper
Post by: madlabs on April 13, 2013, 09:30:36 am
Oz, I usually work like you and build things out of what I have. My schematic generation and product development are like yours. But David's board looks so sexy! David, any chance of a to-scale jpeg, or I'll see if your CAD is compatible with mine. Those boards will be a snap for me to make here at home.

Jonathan
Title: Re: Electric Fence Zapper
Post by: David HK on April 13, 2013, 04:15:23 pm
Oztules and Madlabs,

If you can down load free software from Express PCB ---- this URL   http://www.expresspcb.com/expresspcbhtm/download.htm     I can send you my files for the Schematic and PCB directly. From these you will be able to print out actual size and enlarged sizes up to A3 if you prefer.

Direct from the horses mouth will avoid losses in clarity through different software and scanner mediums. Please PM me with your E-mail address and I will send when ready.

You may be surprised how nice and clear the circuits appear on-screen. I have checked the PCB layout against the Schematic and everything links exactly.

Please note that my AutoCad file of the circuit layout is a bit rough and ready and was done for the purposes of circuit tracing only.

Okay, so far so good. Next step, assembly of parts and coils. Thanks for the tip on the PCB spade connectors, I also have a fair bit of gear on order from RS components and it should arrive this week. I will try another visit to local scrap yards and see what I can find.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 18, 2013, 05:25:43 am
Here is my end of this week roll up.

In the above note I mentioned that I would devote time to collecting parts and other related work.

Most of the parts have been ordered through RS Components Hong Kong and will arrive in the middle of the week ending 27th April 2013.

I did discover one mistake with the triacs I ordered. I selected a type that had insulated tabs whereas in this design I need non insulated tabs. You will see later how I link the tabs with a bolt and copper spacers to a thick copper winding wire that lands on the board. In helps make up for insufficient contact area on the middle leg of the triacs.

Documentation has been useful and I now have an Excel file with multiple sheets showing different things. In one sheet I have drawn up a table showing wire diameters and the theoretical number of turns that can be done on the width of the ETD 49 bobbin. I have subsequently wound a bobbin with 0.8 mm wire and discovered that instead of the theoretical 20 turns of 2-in-hand, I can only achieve 18 turns in a single pass. The difference is of course due to enamel thickness on each wire plus a minor amount of slippage space due to the single pass and non over-lapping requirement.

Other documentation covers capacitor energy values in Coulombs and Joules. Another deals with the inescapable fact of dollar cost which does not bother me too much since this is an advance birthday present.

The coil winder metalwork alterations are more-or-less completed except for an arm to hit the counter each revolution. This should be in place by the weekend.

The PCB layout has been refined with minor cosmetic improvements but without change to the overall layout. Warning text has been added for obvious reasons.

A good size mounting board has been obtained and is yet to be equipped with stand off rubber feet.

The elusive 50uf 600 volt capacitor continues to be a problem and in the whole of Hong Kong I have found one shop that sells high voltage capacitors which are mostly for very expensive sound systems. The cost is in the Cleopatra’s dowry range. As an interim measure I still have a 50uf 450 volt capacitor which is easily purchased locally. 

On the subject of AC working voltages and DC working voltages for capacitors, this URL touches on the subject http://armyintelligence.tpub.com/IT0351A/IT0351A0015.htm

One other thing on large AC capacitors - the one I have is filled with vegetable oil. Does it make any difference if this is laid horizontally or vertical for operation?

On the subject of testing I have some 1 Ohm wire wound Powerohm resistors which I found in a local scrap yard. One is used as a dump load for Ghurd’s famous contribution to electronic science, and the others are waiting for rainy day use. The relevant website is here:-   http://www.powerohm.com/resistorLanding.aspx?partNumber=WR100

Are three of these any use for testing the main coil output? If not, the local pigeons that roost in my mango tree and crap all over the backyard floor are in for a shock.

Back to documentation again. I have cut out most relevant thread entries and pasted them into an MS Word file. Thereafter I have spent a couple of hours amalgamating everything into a logical story based on a typical 12 VDC system. It covers quite a lot of what has been written above in note form.

I have also taken the time to study other commercial electric fence systems sold as well known brands in the US of A and Australia. I have created an Excel table for Model, Distance and Cost for Gallagher (USA) electric fence machines. The longer the distance the more expensive they become.

The PCB design now has six mounting holes – one in each corner and two roughly middle board.

The wiring links to the PCB have been “planned” to cater for two types of connection – solid and reliable soldered wire connections, and, push-on and pull-off spade type. I am wary of the push and pull spade type because enormous pressures can be applied to the circuit board if they are stubborn in each direction. The presence of two centre board mounting and locking down  holes will go some way to alleviating this problem.

The fence line testing instrument sold in Australia seems like a nice bit of kit and someone has obviously put a lot of thought into its design.

I note in one comment on this topic Oztules mentioned the use of lower value capacitors for shorter distances. Is it possible to make up any form of table relating one to the other? Also, apart from different capacitor values, what would be the knock on effect in changes to the circuit generally?

So it has not been an unproductive week and the next one should see a significant move ahead.

David in HK










Title: Re: Electric Fence Zapper
Post by: oztules on April 18, 2013, 09:46:04 pm
Yikes... I just build the thing and turn it on.... wait for the smoke to clear, then rebuild until it works.
450vac cap is perfect for the job, and all I use. The link you pointed to at least shows that is correct.

You could use lower volt caps in series config for the same effect. The DC in this case is behaving like low freq and high freq ac, but the electric field is continuously changing.

Smaller caps only change the rate of charge the oscillator runs at. Small caps, you will have to change the divider network on the transistor as mentioned previously in the text.

MUST keep rate of charge to >= 1 second for health and safety reasons. Dont let it pulse fast, you need time to get away if you tangle in it.


The resistance to mimic the transformer is difficult to determine, as it is the impedance to the pulse that stops the triacs from over current collapse. Their surge is very high, but a dead/near short rather than an impedance will behave differently. The impedance sees it as half a pulse of MHZ frequency voltage, so the impedance will look very different to the resistance in this case. Even winding 20 turns around some heavy steel will help I suspect.

Having said that I=E/R so 600/3=200A, the traics should handle that fine as a short surge.

"The longer the distance the more expensive they become."... I have seen one of these over power a high end unit ($3000).... it's not rocket science....otherwise I would not be able to do it I guess....


.........oztules

Title: Re: Electric Fence Zapper
Post by: David HK on April 20, 2013, 04:30:40 am
Saturday the 20th April 2013.

Most of the hardware assembled. In the photograph are:-

the main mounting board with power supply connectors at one end and the mains transformer at the other, a full size print of the PCB with the ETD 49 coil containing the two primaries, the capacitor, symbolic form of the mains transformer, the coil winder just in view to the right, and the copper pipe is for spacers between the tabs on the triacs.


[attach=1]
More next week.

Dave in Hong Kong
Title: Re: Electric Fence Zapper
Post by: David HK on April 20, 2013, 05:11:25 pm
For those that are interested there is an article on electric fences at this URL


www1.foragebeef.ca/$foragebeef/frgebeef.nsf/all/frg36/$FILE/fenceenergizer.pdf (http://www1.foragebeef.ca/$foragebeef/frgebeef.nsf/all/frg36/$FILE/fenceenergizer.pdf)
cut and paste this into the menu bar and it should work

What caught my eye was the very rough rule that one Joule  is equivalent to about 6 miles distance. I have already cut and pasted a lot of data for Thunderbird, Gallagher and Patriot electric fence manufacturers and the above rule seems to be ~ about ~ the norm.

Dave in HK

EDIT: I made the link clickable. Tom
Title: Re: Electric Fence Zapper
Post by: David HK on April 20, 2013, 05:39:48 pm
A bit more from my studies this Sunday morning.

Joule range: This charger puts out a 0.19 joule pulse on a 500-ohm circuit and a 0.16 joule pulse on a 100-ohm circuit

The above statement can be found in some website advertisements for electric fences.

Oztules, do you have any idea how an individual machine could be selected for one or the other? Or, is it a play on words meaning two separate machines?

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 20, 2013, 06:34:21 pm
"Oztules, do you have any idea how an individual machine could be selected for one or the other? Or, is it a play on words meaning two separate machines?"

Not sure what your saying/getting at here.... so I'll try this scattergun approach.
1 Stored joules are just that.... stored joules thats the 1/2e^2x Farads

2. Energy is energy, the rate it is expended is power.

3. If you have different impedance fences ( not resistance) you will have different characteristics to contend with power wise, but the energy delivered into the load will be dependent on the device matching the load... heard that before haven't we.

4. A scabby transformer with too little iron, will suffer disproportionately from loaded to unloaded fences than a decent core transformer.

5. Once the energy stored is known, and is a constant, and the switching losses are known, and called constant.. then the load matching is all down to the transformer.
 
6. If you look at the midrange units that claim long fence lines, they all seem to have under cooked transformers. They get around this expensive mismatch by using loads of farads, and just assuming/allowing the losses in the transformer matching, using lots of stored joules, and then losing lots of the joules in the transformer.
I have seen some units of modest power, using 300 uf or more, just to match my little one with decent microwave transformers.

7. For my money, there is an awful lot of rubbish written about electric fence units. They are fundamentally simple, and there is nothing mysterious about their workings, or energy / power outputs.... it is simple physics.



not sure if any of that covers your question/s, if not ask it a little differently, and i will try again.


Edit: I said impedance not resistance. Although this is essentially a DC device, it behaves just like ac because of it's rising and falling wave front... so it is frequency dependent on it's transmission in a lot of ways ( other wires in the fence not connected to the unit, the ground etc, capacitances and inductances all over the place... hence impedance not resistance.

That said, resistance is important too, as the grass growth loads the fence up, the  resistance to ground decreases, and this also changes the inductance properties too.... it is a suck it and see situation, and you can calculate roughly with resistance, but you won't then be able to explain the readings when you go out into the real world....... but make no mistake, a low resistance across any part of the fence makes a huge difference.... but not as much as I expected either.

You can find old wire from a near fence tangled up in the electric fence wire ( hot wire run along the front of a normal fence etc), and although it is a direct short to ground, and you foolishly think it will be a zero fence... your eyes will still light up if you touch it. The short to ground never seems to pull the voltage down to anywhere near zero.... and of course when you untangle it.............. sigh ... never learn

This is also  noticeable in a long fence when you find the voltage miles from the unit is higher than at the unit. I suspect standing waves in the fence and/or nodal points.



.....................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 20, 2013, 07:19:13 pm
Oztules,

You really are a wizard on this topic so I take my hat off to you.

I only asked the question above because I was curious about why someone would write about a comparable performance difference which most readers would not have a clue about. Your scatter gun answer does indeed illustrate the more deeper background of physics and well known 'laws' which apply to the topic. The answers do indeed make sense.

With regard to your paragraph 7, how right you are. In paragraph 1 you will be pleased to know that I played with that formula early this week and have an Excel table worked out for various Farad and Voltage values. I surprise myself sometimes.

I am learning fast.


Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 20, 2013, 07:32:09 pm
Tom,

I missed your Edit note in the above post, so thank you for making the URL work by "click" on demand.

I assume your following this thread with avid interest. 

In a week or so I should be able to post the finished project in terms of material assembly. Thereafter you may be reading about the great magic smoke adventure, or, a brief encounter with pain. Chinese swear words are far worse than those used in the Western language. By the way and to avoid confusion, I am Anglo Saxon Brit (white still) and not Chinese although my wife is.

I am still mulling over how to test the output and I have pondered the idea of putting an earth stake into the ground near the roots of my mango tree, and then wrapping the other  transformer "contact" end around the tree trunk. I am rather concerned that the tree might jump out of the ground and attack me.

Unfortunately there are no bears, crocodiles, wolves or such like around here otherwise I would be tempted to tie one end to a cattle prod and chance my luck!

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 20, 2013, 07:43:24 pm
I have a box of 2w 47ohm resistors. I usually put 3 or 4 in series for 200R,... then put them directly on the output of the microwave tranny.
This usually gives you  2 or 3 pulses which yo will hear, and then by about the fourth, the enamel will start to get blasted off the resistor casing.... starting with blue fingers of spark walking across the surface, and quickly getting to loud bangs, big blue sparks, that you can hear 100 feet away as you approach it.

If you have a fence tester with current abilities, you will probably see 6-8000 volts at 40 amps or so, if you use more cap, then you get up in the 10000@40A and beyond.... my tester only goes to 40A and 13000v

After a minute or so, it settles down to big blue sparks across the resistor bodies, and parts of the enamel blown off until the air takes a lot of the energy as plasma dances along the sides of the resistor.

At this point, you can bet it is working well enough to keep any beast at bay.


I think I'm just misguided somehow.




..............oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 21, 2013, 02:52:55 am
Oztules,

I have been studying the main transformer windings in advance and have stumbled across a question that I cannot find the answer for via Google.

The primary winding in your notes is Bifilar, 9 turns, 2-in-hand 1.8mm diameter. The transformer bobbin I have is 51.5 mm wide so that offers a single pass of wire at 14.3 turns. However, that is bare wire only, so with enamel on the 14.3 turns could easily drop down to ~ 9 turns.

I have checked your hand drawn circuit sketch and cannot see any special reference to a “start” point for either wire, Am I correct to assume its just two wires with each end of the pair being soldered to the relevant tab on the transformer?

Secondly, I have oodles of 1.6mm wire given to me some years ago which is in want of a job. Could I go with 1.6mm or is 1.8mm essential?


Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 21, 2013, 03:16:29 am
If your not going for broke, and just want to run 30km of fence.... then a single 1.6 would do fine. It does not seem to matter how you hook the wires up on the primary. You can use two in hand, and get lots of power, or you can series them, and drop power, and widen the pulse width.

The pulse width will be a product of the impedance of the primary. The bigger the fencing wire in there, the skinnier the pulse, the higher the current and voltage, as the rate of change .. discharging the cap will go up markedly with lower and lower impedance in the primary.

A very skinny pulse will show up as a very high output from the unit. but will degrade faster with distance from the unit, as the inductance and capacitance of the fence and general impedance of the  surroundings will have a greater impact.

The closer to a sine wave you get, the better the transmission, and lower noise.... so it is all a compromise.... as usual. The toroid and the 2uf caps help shape the wavr wider just for this purpose.

two in hand of 1.6mm will be fine if you can fit it in, but one will be good too.



............oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 21, 2013, 03:44:16 am
So there are four choices:-

2-in-hand x 1.8mm diameter wire; or, one single run of 1.8mm diameter wire, or

2-in-hand x 1.6mm diameter wire; or, one single run of 1.6mm diameter wire. each of the foregoing to occupy the bobbin width or thereabouts without over lapping.

I have written this out in the long winded way so that I understand it.

You mention "in series".  What exactly does this mean? This is the only part that confuses me.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 21, 2013, 04:19:57 am
Well.....
This is right up your alley... lots of calcs to do (I just wind and find out the hard way...)

It comes down to how much winding window you have, and how much power your after.
Parallel or series..... you will have two independent windings of say 9t on the primary, you can series them to 18 turns, or parallel them for 9 thicker turn equivalent

If you want to experiment, make it so you can series or parallel and see the difference.... for power your after parallel to keep the resistance/impedance down to minimal.
For milder power, and happier triacs, you can series them, and lower the output, and increase the wave width... all choices for you.

I suspect that for your bobbin, 9T 2 in hand is 2 layers, not 1 like mine. If so, your eating into your window for the secondary, and remember there is probably 7 or 8 layers of transformer paper to jam in there as well.

In your case , I'd use only one layer of as big as i can get for the bobbin, and if that means only 1 in hand so be it. The secondary takes a fair bit of room.. mostly because it is neat and paper insulated between layers. Thickish transformer paper will mean you don't get to use the valley between wire turns, as the paper will keep it all at paper layer level, so window gets away.

Not ever having been bothered with calculating my doom, I just wind it and suffer.... then have enough information to fix it up if necessary.... I am not even remotely the best person to ask for this part I suspect.



...................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 21, 2013, 06:19:09 am
Oztules,

Thank you for the last two notes. A couple of points arising. I am hoping to make the 'machine' as a replica to the hand drawn sketch shown early in this thread, then there is a yard stick to work on.

The item that has confused me in the last two notes is the reference to different types of bifilar coil windings. I understand there are four, but I cannot find one single sketch on Google that illustrates them. As a last resort I have made up the following sketches on AutoCAD showing what I "think" they are. Perhaps you could take a look and let me know what my score is.



Dave
Title: Re: Electric Fence Zapper
Post by: oztules on April 21, 2013, 09:14:39 am
"I am hoping to make the 'machine' as a replica to the hand drawn sketch shown early in this thread, then there is a yard stick to work on."

Bets of luck with that, I have made many, but no two were the same. Every transformer I got hold of had different plate numbers or physical sizes, and so different character. You will have to fiddle with the divider network for the trigger and the oscillator for every oscillator transformer/transistor combination, and drive voltage..... it is very very flexible, and by controlling both those dividers, we can get them the same.... but the power transformer will give it it's ultimate grunt quotient... for the same voltage and capacitance.


Now pictures of coils.

No 1.
Will give you no output emf, as cancellation is complete.... look at it carefully and follow the emf of a single half cycle ( can treat it is a battery perhaps for this purpose, as it has sign and potential at any frozen point in time).

 Note that they have identical emf in the same sign, so you have effectively added one .........say 12v battery .....in series with another 12v battery, but have joined the two positives together, and have the wires going to the two separate negatives..... full cancellation.... 0v

No2. Is parallel two in hand, and will result in say 2 12volt batteries in parallel, positives joined and negatives joined... twice the currrent at the same 12v potential. This is how I wind mine... gives twice the current handling, at 1/2 the resistance/impedance.

No3 and 4 I'm not sure how to interpret ... nor has anything to do with bifilar as I know it........... as the windings have to be identical as they are two in hand.... cant counter wind.... they are identical, thats why we do it .... they share the same magnetic and resistive events at identical times in the sine/pulse wave at all points along the wire. The resistance of both coils is the same at all times at all points along the winding.

The best thing about bifilar is the identicalness of the windings. Remember, you will get some phase changes in resistive inductors, so you want the resistance to see the same things at the same times if in parallel etc...... we can use  this phase relationship in single phase induction motors.

The start fields and run fields are two different thickness windings, and we get some phase alteration from this alone, as well as the physical magnetic position, and the added capacitors.....the caps and different thickness wires all add to give the starting torque to the rotating fields that the rotor sees............ so if were to counter wind, we would need to wind one first then the other in the other direction.... by necessity, it will use a longer coil path for the second winding..... this will experience different resistance, and then different phase character ( be it ever so small).......

We could say wind them side by side to keep the coil path the same length, but we lose coupling, and get a leaky transformer ( more magnetic leakage, less energy can be transferred, as the driving field is "further away" from the driven coil, so the magnetic flux is less than ideal) If we wanted to get tight flux low leakage, we would wind half the primary, then the secondary, then the other half of the primary on the outside... then the secondary sees flux from the outside and the inside, and sees a stronger changing field for the same magnetizing current. Particularly useful for pulse width modulation transformers where it is important to keep the leakage down to a minimum.

If you unwind a computer power supply power transformer, you will find this coil structure.... getting side tracked now..... oh well...

Series connection of bifilar windings can  be seen in toroidal transformers that you can buy, and you can either parallel or series the secondaries for twice the Y voltage, at X current, or parallel for twice the X current  for the same Y voltage.

You can see that to put the secondaries in parallel, we need the coils to be identical, or they will work against each other where they differ slightly.

So series connection is still your  No1 diagram, but join one of the starts and an end together with a jumper wire... the remaining two "empty" wires left over will be a start and an end...... and be at  twice the potential of a single winding/coil ( and twice the resistance/impedance).

So, we don't need to counter wind, we just use a jumper from the end of one coil  to the start of the second... which effectively gives us counter wound, but with two identical in every way...  coils.


Did that help, or just muddy things up.




......oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 21, 2013, 04:39:41 pm
Morning Oztules,

I now have tea and biscuits and the birds outside are singing their hearts out for another grey start to the day.

Thanks for clarifying the situation on coil windings above. If counter windings have no bearing on your circuits they can stay out of the picture lest readers become confused. I have however updated the first two sketches and have repeated them below.

I think my earlier use of the word "replica" was wrong and I should have used the phrase "similar materials and design concept to the hand drawn circuit earlier in the thread". Sunday saw some progress in the form of a cradle to hold the capacitor and the first of six mounting studs for the PCB. Today (Monday) I may be able to get the secondary wound on the ETD 49.



Dave
Title: Re: Electric Fence Zapper
Post by: David HK on April 22, 2013, 01:18:02 am
Oztules,

Main transformer – secondary winding – advance thinking.

I note the need for transformer paper between each pass over the bobbin. You mention up-turning the sides by 3/16” (~ 5 mm) for good insulation to prevent arcing.

I have transformer paper in two different thicknesses – 0.015 and  0.03 mm - and plan to cut long lengths to cover the bobbin layer and up-turn each side – cut to length as the layers progress.

I was thinking of using a vice  (or experimenting with the wife’s iron) to  press the up-turn so that it produces a nice right angle between the layer and the bobbin wall. However, I can see a problem - as this curves around the bobbin the small up-turn will want to crumple and deform owing to the curvature. My first solution would be to cut nicks into the curving region to remove the stress. Is this what you do, or, do you just wind on regardless of paper deformity?

Illustration attached.



Dave

Title: Re: Electric Fence Zapper
Post by: oztules on April 22, 2013, 03:40:05 am
Dave


I don't recall the turning up part, I would expect i said to have 5mm of paper beyond the end of the winding...

So if you have 30mm of copper in a neat layer, then you need a 40 mm bobbin, so that the paper is 40mm wide, the copper 30mm wide, and you have your 5mm of vacant space at each end of the winding. That way the spark would have to jump out the end then back in to snag the next coil... which won't happen.

Turning it up just makes a simple job more difficult, and the nicks would circumvent the good work ... so nothing gained.


.......oztules

edit....... thinking about it, it would do no harm to cut the paper 10mm too wide for the bobbin space, and  then fold up the 5mm ends back onto the paper itself... maybe even iron them flat so they hold and behave as a normal piece of paper with a "seam" on each end

... that way you make a delineation .03mm high for the wire of the next level to wind to... not too shabby, and will give yet another barrier to the sparks trying to get out the end... interesting...
Title: Re: Electric Fence Zapper
Post by: David HK on April 22, 2013, 07:21:11 pm
Oztules,

Following up on your last note I have resorted to a combination drawing to try and understand if I have got your comments right

Early in this subject thread
The main transformer is a different story.  High voltage, and very high currents exist here, and each layer needs to be carefully wound, with transformer paper exceeding the layer width by about 5mm each side. This will make it very hard for the arcing which would occur instantly without this protection. (this is where I picked up the paper being the bobbin width plus a 5 mm turn-up each side).

Drawing 1
So if you have 30mm of copper in a neat layer, then you need a 40 mm bobbin, so that the paper is 40mm wide, the copper 30mm wide, and you have your 5mm of vacant space at each end of the winding. That way the spark would have to jump out the end then back in to snag the next coil... which won't happen. (might work on a machine wound coil with an ‘auto traveller laying the wire’, and hand wound large diameter wires. Small diameter wires might ‘fall off the edge’.)

Drawing 2
thinking about it, it would do no harm to cut the paper 10mm too wide for the bobbin space, and  then fold up the 5mm ends back onto the paper itself... maybe even iron them flat so they hold and behave as a normal piece of paper with a "seam" on each end

... that way you make a delineation .03mm high for the wire of the next level to wind to...

The world ‘end’ may be the understanding problem since most of the above comments relate to width.

I am not sure if I am still confused.

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on April 22, 2013, 08:18:02 pm
From what I understand of Oztules description you'd start with a piece of paper 50mm wide.
Fold 5mm in from one side, and 5mm in from the other side, and iron flat.

You now have a piece that is 50-5-5 = 40mm overall that will fit in your 40mm wide bobbin,
and a coil-winding-space of 40-5-5 = 30mm inside the indentation to wind your coil in.

Ending up with 30mm wide coil, with 40mm (ID) bobbin, and 5mm clear space either end of your coil.

(But I could be wrong!)
Title: Re: Electric Fence Zapper
Post by: oztules on April 22, 2013, 08:27:11 pm
Ross might be wrong, but he's not.
Thats exactly as I had hoped it would be interpreted.

.................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on April 22, 2013, 09:38:00 pm
Please send me an Australian thinking cap.

I think I have got it right this time, So in fact the 'lip' of the folded over piece of paper indicates the extremity width of coil wire?

This is interesting because an air gap of 5mm each side of the winding plus the plastic thickness of the bobbin (2.2mm) = 7.7mm puts the coil some distance from the laminates surrounding it.

Dave

Title: Re: Electric Fence Zapper
Post by: oztules on April 23, 2013, 04:46:56 am
"I think I have got it right this time, So in fact the 'lip' of the folded over piece of paper indicates the extremity width of coil wire?"

Yes you seem to have it right this time.

"This is interesting because an air gap of 5mm each side of the winding plus the plastic thickness of the bobbin (2.2mm) = 7.7mm puts the coil some distance from the laminates surrounding it"
All true, but the laminations it is farthest from do not cause problems for us. The core it is wound around is what counts, the rest of the transformer laminates are there just for a decent path for the flux to travel around the place.  Normally they need to be propionate to the center leg, but their proximity is of no importance in real terms... as the flux travels through the laminates very very well, it is getting it into the laminates in the first place thats critical, and that calls for tight coupling.


In this particular case, it is going to be so super saturated as to make no difference if the rest of the transformer did not exist, and just had the core laminates. It would probably work just as well... possibly better....


Lets be clear about this, I am NOT an engineer or even a hopeful offsider, I just play with this stuff when I need to. Someone else with better understanding is most welcome to correct me on any point........................... I am the village idiot after all... ( my wife says so.... so it must be true....)



.....................oztules
Title: Re: Electric Fence Zapper
Post by: rossw on April 23, 2013, 05:03:08 am
I had an ancient old electric fence energizer when I was a kid... the coil was a huge lump of copper all bound and dipped in some sort of goop...

The interesting thing is, it was wound on a single, laminated core - about 4" long x 3/4" square.

It worked fine, without all the extra "stuff" around it.
Title: Re: Electric Fence Zapper
Post by: David HK on April 23, 2013, 06:01:30 am
Okay so far so good.

Tomorrow all the RS Components stuff arrives which means I can finish off the position for various spade fittings on the PCB.

I have the transformer paper and varnish and the old transformer has had its copper coils removed, ditto for the veneer of varnish around the bobbin surface.

Back to the main transformer - I intend to go for the 1.8mm wire and try for 9 turns at 2-in-hand and see what I can get on in the 51mm width. Taken across the width of the bobbin it will be somewhere between 9 and 14 turns.

I am in a quandry about the secondary winding which is noted down as 200 turns of 1mm.  The bobbin is 51mm wide and I would like to try the concept of a 30mm wide winding as has been illustrated today. However, that does not mean 30 wires per layer because the enamel thickness will reduce it to say ~ 29.

The bobbin wall is 14.5mm high so subtract the primary thickness and according to a rough order of calculation using 1mm + paper, 1mm + paper etc on Excel and it should be possible to obtain 8 secondary layers leaving 4.7mm at the top for coverings. Something like that. Taking the rough arithmetic further 29 wires per layer, times 8 layers, suggests 232 turns.

On the primary winding I am thinking of no connector tabs at all on the transformer and instead just take the 1.8mm wires direct to the PCB and solder on, or, solder onto a female tab connector.

Any views or suggestions?

I know you're not an engineer, but you are certainly a very clever amateur who should be an engineer. As for me its too late in life to start again, I just enjoy the days with something interesting to do.

Nearly there, but still a lot of fiddly work to do.

Dave

Title: Re: Electric Fence Zapper
Post by: Norm on April 24, 2013, 10:53:56 am
Mostly what I'm thinking is pidgeons and pidgeon pie  LOL
Norm.
Title: Re: Electric Fence Zapper
Post by: David HK on May 02, 2013, 10:40:20 pm
It works! Yes, it really does work. Thanks Oztules, another one of those things to be studied and done in a lifetime.

I will confess to having one of the primary start windings around the wrong way at first, but when I realised the mistake and corrected it all went well. I also now understand what Oztules means by 'playing around with this circuit'. Once the various coil turns, input voltages, and expected output voltages are set up into an MS Excel worksheet all sorts of voltage permutations and coil windings are possible. The same goes for the capacitors. Taken further still, even the ohmic resistance of fence wire is important when designing a system.

Enjoy the Heath Robinson photographs for now. I will post again later with a more detailed set of notes regarding the construction arrangements.

David in HK
Title: Re: Electric Fence Zapper
Post by: Wolvenar on May 03, 2013, 01:16:43 am
Awesome David!!!
Looking forward to the details, I might have to build one, if I ever find time.

Thanks guys for pursuing this and sharing with us here.
Title: Re: Electric Fence Zapper
Post by: oztules on May 03, 2013, 03:52:27 am
Nice to see it done. I hope you don't sample the output ;D ......... although in some macabre way...... it is always funny watching someone else touch the output.

???? there is a core in that power transformer ... isn't there?  It will work  without, but it will stress the triacs unnecessarily if there is no core at all. The resistance of the primary is very low, and a bit of inductance would be a good thing.... and the current transfer will be better.

Well done, and nice to see my crazy stuff work for someone else.



....................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on May 03, 2013, 04:14:49 am
Yes, there is a core inside the main transformer. The original laminates were 'E' type so I cut out the centre section of the E and stuffed it in.

And like all things in life it has now stopped working because, I believe, of a short in the main transformer secondary. I took the thing 'down town' and let one of the local old Chinese boys do the secondary winding and he was insistent on using masking tape as the insulator between layers.  I hadn't got the heart to stop him as he was doing me a cheap favour. I think this is the reason for the secondary failure.

My plan is to unwind the the secondary and rewind it much more carefully with proper transformer (magnet) paper between layers and also avoid contact (lying against perhaps is a better description ) with the start end of the coil.

Nevertheless, this thing really whacks out some power and the three 47 Ohm resistors in series at the output end were not at all happy with serious blue arcing coming out of the sides. Having seen this I have no intention of touching the the wire for a quick look see.

Will report back next week when I have sorted out the main transformer.

Oztules, while your around, what does the variable resistor do? I have twiddled it and see little effect.

So far so good. learning as I go, as usual.

Dave in Hong Kong

Title: Re: Electric Fence Zapper
Post by: oztules on May 03, 2013, 04:39:53 am
The variable resistor changes the step off voltage, but as I mentioned previously somewhere, I use too low a value to make much difference, it is really for fine tune at 250k, if you increase it to 1m or more, you will have more control, but the timing will change markedly too, and you may be inclined to not bother replacing a fixed resistor, and let it pulse too quickly...... that, and I had oodles of 250k things around the place at the time.

Best to get the capacitance you want, then work backwards to find the right values to give you the step off, and timing right, and just a bit of twiddle with the pot. The divider resistors and transistor selection of the oscillator will change the charging power, and the divider and pot can fine tune the step off and timing.

It makes short work of my 47R 2watt resistors, they survive for maybe half a dozen pulses at most before rupturing and spitting blue fame along their length.... and spit off a bit of enamel to boot. too... careful with the eyes, sometimes it is quite good at ejecting the enamel off the coating of the resistors.

It is a bit scary too.

I suspect the secondary is toast. If you put the two output wires within a few millimeters of each other, they will arc straight through the enamel of the wire... makes for big sparks as the energy transforms the lacquer into plasma.

If you can hear the oscillator wind up, and hear the grunt of the transformer, and it cycles again, you can be sure the secondary is the number one suspect.....number two is your flywheel diodes are short.
If the oscillator just starts to wind then holds a low frequency, it's the triacs . If it goes halfway up the pitch scale, then the one of the rectifier diodes are shot.

Measure the cap voltage is another way, it it rises to 450v-600v, then all is well with the charging side, and it has to be the transformer or or flywheel diodes. If your using 6a04 diodes or better then the transformer is number one suspect


EDIT: just looked at your picture...... flywheel diodes look very small.... what are they.... look more like 4008 etc.... in which case they are probably shot to hell. They don't have the surge capacity to hold this thing down.

edit2: Yes just looked at your schematic, and in small print I see 4007 diodes..... they will not survive long at all. Fix this before you tangle with the transformer. Almost guaranteed the diodes are toast and short.... my old eyes missed that before.... sorry.... look at this:

[attachimg=1]




.... see the big fat diodes there.

Stay wary my friend.


..................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on May 03, 2013, 04:55:03 pm
Your right about the diodes not lasting, I have blown two already (1N4007 types).

Will see what I can do to replace the lot. 


Thanks also for your last note on the things to look and listen for when the things blows a gasket.

I have some ideas to make a significant improvement to the insulation of the main transformer secondary and will attempt that in the next few days.



Dave

Title: Re: Electric Fence Zapper
Post by: David HK on May 04, 2013, 07:13:53 pm
Oztules,

Thank you for the last set of notes.

I have changed the diodes – big mothers aren’t they!

The main transformer was shorted in the secondary coil, so I unwound it back to the start. I then rewound it very carefully and each winding layer is now separated by a piece of good quality transformer paper. After reassembly, I connected it up again and it works.

I suspect the thickness of the transformer paper has changed the performance a little. Previously, with the ultra thin masking tape separator between the winding layers, the sparking over the three 47 Ohm 2 Watt resistors in series was spectacularly vicious and frightening. With the latest wind using modestly thick transformer paper the sparks just make it out of the surface of the resistors. Nevertheless, the power being produced must be substantial just to make this happen.

For your information I am keeping the circuit schematic up-to-date and have revised it to include the latest information on the diodes and the triacs (non insulated tab type).

Secondly, the PCB layout has been updated to take into account the larger size of diodes. I will post the final circuit schematic and PCB layout in the next few weeks after all the experimental work has been completed.

I now have one more PCB and will build another identical machine in the next week or so.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on May 04, 2013, 09:00:57 pm
It should run without breakdown now.

I have yet to see a transformer failure... so your a first.

 I have seen diodes and  triacs fail in the early days, but not any more now the teething problems have been teased out. Some have been  running for four years now.

The sparks... it could be your man wound tighter than you, or the extra space is giving a looser coupling. You can remedy this by using only half the primary as the first winding, and the other half the last winding. Then the secondary is trapped between the primary layers, making the coupling very tight.

The other thing you may find, is the humid weather over there has gotten into the resistor body in the intervening period since last use/terror.... perhaps because of the ash/carbon  on the surface, and that if you use three new ones, they may well behave like the originals for a bit. This behavior changes radically from scary to fairly benign, depending how the resistor is being destroyed.

You may find the dynamic loading has changed markedly, rather than losing as much power as you surmise at this stage. If you had a meter that did current and voltage, it would tell you all.



......................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on May 04, 2013, 10:34:45 pm
For reference this Sunday morning (5th May 2013)

Volts                  13.7  (From RE system)

Current draw     0.34A

Watts                4.65


Dave
Title: Re: Electric Fence Zapper
Post by: David HK on May 09, 2013, 08:08:11 pm
Hello Oztules,

Another week of updating and learning.

The first PCB now has five LT6A4 diodes – photograph somewhere below. I expect its overkill, but the machine works fine with them. I left D1 as a normal 1N4007.

I did a continuity check on the toroid and discovered that there is a short between the ferrite coil former and the wire. I have subsequently wrapped two new ferrite rings with insulating tape and then carefully wound 1mm diameter wire onto them. A second check reveals no continuity problem so I have given both of them two dips in varnish and will replace the one on the first PCB when drying is complete.

I am now making up a second PCB which will avoid many of the shortcomings and pitfalls made on my first attempt. There are two interesting comments to make with this second unit.

Firstly, I have wound on 15 turns of two-in-hand 1 mm diameter wire onto the ETD 49 bobbin. That’s all it could take in a single pass. I have since covered this with ‘thin’ magnet wire paper. The Start and Finish ends are right this time so it should work when all is complete.

On the first ETD 40 coil I used 0.8 mm diameter wire and obtained 18 turns of two-in-hand. I then ‘semi-bundled’ the secondary directly on top of the primary (no paper separator) and laboriously wound on the wire turn by turn and achieved 604 turns with room for more ~ 20 to 30.

On this second coil I intend to adopt the same procedure and see what can be achieved in the way of turns between 400 and 600.

I have been to the local scrap yard and discovered piles of transformers that range from small two-hands-to-pick-up, to slightly bigger units that need two or three men.

Initially I thought that the second transformer I purchased was the same as the first, but after dismantling it, it is about 33% bigger although the width of the bobbin is the same. A photograph appears below. My question about this is:-

If I wind the same 11 turns of 1.8mm wire for the primary and 400 turns of 1mm for the secondary I will end up with a larger copper mass. What does this do to the voltage, and/or the power output?

Other improvements to the PCB design are very cosmetic and not easily seen by the naked eye, but are:-

Two adjustments to component spacing, and new positions for the larger LT6A4 diodes and associated through holes.

I have also made up an Option B PCB layout which puts the TIP 31 on the left hand side of the board and incorporates through holes for a clip on type heat sink for it. I don’t actually know if this is really necessary, but there is room on the PCB to accommodate the feature if required.

The board design ‘as is’ has room to accommodate one or two more triacs. Is there any merit in adding more?

This is a really interesting project.


Dave
Title: Re: Electric Fence Zapper
Post by: David HK on May 09, 2013, 11:57:09 pm
My apologies, I failed to include this photograph in the above set.




David HK
Title: Re: Electric Fence Zapper
Post by: oztules on May 10, 2013, 05:33:33 am
Ok, more triacs the better the current capability.

More turns on the power transformer does not mean better performance. The back MMF of the secondary will work against you.
Probably 200-250 turns is probably even a bit too much..... You may do better with a bit less. Remember the amps in the secondary are very very high >40 amps at full loads........ and lots of turns means lots of amp turns.... big back MMF may cruel your expected gains. Open circuit, it will be impressive, but under load may  drop well below a 200 turns version.... experiment and see where the gains drop off. Every core is different with my stuff, as my microwave trannies seem to be all different.

The core will saturate whatever the core I suspect, so it is something we just have to live with. Bigger is better.... but at what weight?

The whole thing is a big compromise.... but it does work, and different combinations of ratios will yield different results... not all expected either. It is very interesting really, and tells you a lot about magnetics and wave forms if you don't do the serious calculations ( which are out of my comfort zone in reality). Good learning tool really.

More turns on the etd49 really only yields faster rise times for the cap in most cases, more turns on the power transformer may not give you the load capabilities you may expect..... possibly far from it..... I suspect Rossw could tell us both a lot more about this if the truth be known.




......................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on May 10, 2013, 06:43:33 am
Oztules,

Thanks for the note it was very interesting reading. You are right about compromises. Today I spent a minute or so working out voltages to the ETC 49 primary, the number of primary turns, and the number of turns on the secondary to see what voltages would be apparent (mathematically).

In Excel once the formulas are set up its easy to change parameters. I was curious to see what would happen in a 24 volt application and started off working out the voltage divider changes that would be needed to avoid blowing the TIP 31.

After putting the 24 volts into the ETD coil mathematics and projecting the same onto the main coil a lot of winding turn changes are needed to keep the theoretical output below 10,000 volts. So yes, its an interesting machine that one could spend months or perhaps years tinkering with and recording the data obtained.

Found my biggest capacitor in Hong Kong today - 70uf  475 volts AC.

I shall carry on with the second machine and keep folks posted as I go.

Judging by the "hits counter" this thread seems to be of interest to a great many readers so its nice to see a useful idea for a machine slowly being exposed in text and photographic form.

Keep in touch.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on May 10, 2013, 07:06:06 pm
By the time we finish this, this will be the most scrutinized circuit in the universe.

"In Excel once the formulas are set up its easy to change parameters. I was curious to see what would happen in a 24 volt application and started off working out the voltage divider changes that would be needed to avoid blowing the TIP 31. "

As a very rough rule, double the two divider resistances, and it will probably work with all other things exactly the same.
Remember, your power transformer will not care what you run the thing on, it will still get fed 600v only... the diac and diac divider network sees to that, so the power tranny does not change in any way.

The ETD49 can stay the same if you want, just change the divider resistances and it will still work.... although doubling the winding of the primary/halving the secondary will help with impedance matching some.

Luck with transformer calculations.... the oscillator is frequency varied, pulse width varied, and amplitude varied in each cycle.... it is roughly a square wave that changes the frequency from low to high as the load changes, the pulse width changes from wide to thin as the voltage rises, and the amplitude of the wave changes from low to high as the voltage rises in the cap..... how to figure that is beyond me... I use the suck it and see method ::) The universe is a complex place, and I'm not bright enough to fathom it all at once. So 24v operation will require very few changes to work the same.... watch the temp on the transistor as you fiddle the resistances on the divider.

I am wary of spread sheet and modeling in general if ALL the parameters are not fixed in cement. The moment we make an average value, or assumption because we can't give a definite value to something, or there are things at work we don't understand... and so we use some constant to make it simpler... the more useless modeling is... the biggest problem is that it looks so good, we are inclined to believe in them..... at our peril. See economic modeling, and environmental modeling.... never even come close to the truth, and never will as we don't understand most of the forces at work in both cases.... so they allocate a mean value and move on...

The output transformer defies models that normal transformers would use, as it relies on the impedance of the input winding, not the turns to dictate the pulse width, which in turn controls the rate of change of the field... which controls the EMF generated in the secondary. Thats why 200 turns will beat 400 turns on the secondary with any decent load. The currents are very high, and the back MMF is very pronounced, and the whole lot saturated... what a mess to calculate...best of luck with that.

"Found my biggest capacitor in Hong Kong today - 70uf  475 volts AC."

If your after sheer grunt in the output, you can parallel caps, or increase the voltage and series parallel a few caps. The  energy stored has a V^2 component... so doubling the capacitance is double the energy, doubling the voltage is quadrupling the energy. The triacs may need upgrading with more capacitance, and really will need upgrading if doubling the voltage.


You can play with it endlessly, but be careful of the business end, it packs quite a wallop.



..................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on May 10, 2013, 07:28:26 pm
Your up early today.

I am just about ready to start house cleaning and thereafter its my BBQ/Roasting spit cleaning ready for a pork loin roast on Friday (public holiday here). The fare will be pork loin roast with the skin on (crackling), roast potatoes, mashed potatoes, carrots, peas, perhaps cauliflower, gravy and apple sauce. All washed down with beer, wine and whatever. Wish you could come.

My BBQ/roasting spit is all stainless steel and has slowly been built up over 15 years. This includes the BBQ table, forks, tongs, trestle, auxiliary table, and countless other small things that make it a nice talking point when guests arrive. The fuel is charcoal which is common in China and Hong Kong. I may put up a photo next Friday or Saturday.

Thank you for the additional notes, I wish there was a set of machines easily available to observe all the wave forms, voltages etc that you mention. I was thinking of writing a begging letter to China Light & Power to see if the company engineers might have a curiosity interest and help with measurements.

Anyway the next task is to finish machine No. 2.

Dave

Title: Re: Electric Fence Zapper
Post by: David HK on May 24, 2013, 10:36:12 pm
Update for Saturday 25th May 2013.

Machine B is coming along as the photograph below illustrates. There are minor differences with Machine A and cover:-

Coil wire thickness and the number of turns, a larger capacitor, and a home made main transformer coil bobbin.  For this I have resorted to 9 turns of two-in-hand 1.6 mm primary wire, whilst the secondary is re-used 1 mm dia wire (ex transformer) and exactly 224 turns. This allows the In and OUT wires to be the furthest apart on the bobbin.

Remaining work is to wind the secondary on the ETD 49 bobbin and populate the Triacs on the board with spacers and bolt on the Tabs.

This machine should have a greater output than machine A.

For those interested Machine A takes exactly 31 pulses to blast the 3 test resistors (47 Ohm 2 Watt) so that handsome size sparks fly out of them.

I am toying with the idea  of replacing the main transformer coil on Machine A with another home made bobbin which is only wide enough to accommodate 9 turns of two-in-hand 1.8 or 1.6 mm primaries. The existing primary is 11 turns.

Eventually I will document the exact differences between both machines.



David HK
Title: Re: Electric Fence Zapper
Post by: oztules on May 26, 2013, 04:24:16 pm
"For those interested Machine A takes exactly 31 pulses to blast the 3 test resistors (47 Ohm 2 Watt) so that handsome size sparks fly out of them."

Looks like I have created a monster   ... next stop for you is a tesla coil.... get down and make some real sparks.  :)

It is not like those ignition coil things, these things can pull some serious power... albeit for micro seconds only.

Interestingly, I wound a etd49 coil the other day from microwave secondary wire... and it didn't oscillate, checked resistance, no apparent short... wound again... same thing..... in fact got curious, and rewound 6 times with  wire from that secondary.......each time..... nada ......nothing.

I have no explanation.... none.. Rewound with wire from a different microwave transformer... and worked straight away.... tore that off and wound again from the same different transformer, and worked again...... then tore that off and wound from the first transformer..... no go again.

I have no explanation as to why there is a difference between the wires in these microwave trannies. This is the first one to defy the rules in such a decisive manner. When you can load up 500 turns, and not get a peep out of the oscillator, but the DC resistance is the same as wire that works..... well gobsmacked......Zubbly was right... it is magic stuff this electricity.

So I am confounded yet again.



.....................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on May 26, 2013, 05:50:49 pm
Hello Oztules,

Nice to see your'e alive and kicking. How about a dry joint problem for the above scenario? Alternatively connect it to a safe 240/120 volt circuit and see what happens?

Machine B now has its triacs and a re-mounted capacitor. I hope to finish the ETD coil some time this week - at the moment I am busy helping my daughter with her last diploma essay which is due in today (Monday).

I have some more interesting PCB layouts of the circuit which cover an 8 and 12 Triac version. This is achieved by playing around very carefully with the layout of components on the PCB. Both versions provide for a clip-on type heat sink for the TIP 31.

My local expatriate acquaintances are intrigued with the machine and some have said there is a market for this type of thing in Malaysia. They are all awaiting to see what Machine B produces.

My next door neighbour is local Chinese and he has told me that opportunist burglary is rife all over China and such an item would be useful to a lot of people. I have seen electric fences powered by mains voltage around some residences in Shanghai so it makes you think.

Very wet, humid and warm/hot here in HK at the moment.

The weekend should see new photographs and interesting reading.

Dave





Title: Re: Electric Fence Zapper
Post by: madlabs on May 30, 2013, 10:09:42 am
Howdy,

So I got distracted by a water system controller I built, you can see it in another thread. However, just yesterday I saw the bear on my driveway, so it's time to get back to to this project.

Wow, David and Oz, lots to catch up on in this thread. A quick question though David, any chances of buying a board from ya? Tons to do and even though I'd enjoy it if I can short cut this project I would.

Really nice work you two!

Jonathan
Title: Re: Electric Fence Zapper
Post by: David HK on May 30, 2013, 04:18:31 pm
Hello Madlabs,

I wondered what happened to you. The answer to your question is yes.

Could you please wait a few days before going further because I am about to complete Machine B and hope to put up photographs and details this weekend. I am interested in comparing the performance of both machines since they differ slightly in terms of coil turns, wire thickness and main transformer bobbins.

I managed to finish the secondary winding of the Machine B ETD 49 coil yesterday (Thursday) so I should be able to complete its final assembly today Friday. The only hiccup is that today is the last day for the last essay for my daughters year long Diploma course so its a case of me helping her and everything else has second priority.

Nevertheless, there will be some interesting photographs and text to look at in the next few days.

David in HK
Title: Re: Electric Fence Zapper
Post by: madlabs on May 30, 2013, 08:59:01 pm
Davis, no problem on the wait. Take your time. I have a few days of installation and programming of my current project and then I have to string wire on the fence. But I am very pleased that I can buy a board from you! That is going to shave some time off!

Jonathan
Title: Re: Electric Fence Zapper
Post by: David HK on June 01, 2013, 06:17:42 pm
Oztules,

I need some expert advice.

Both machines have ceased working. Here is the story.

I completed the winding of the ETC coil for Machine B and fitted it in. I set up the machine for its first test and on the output side I place the usual 3 pieces of 47 Ohm 2 Watt resistors in series. I turned on the power supply and instantly all three resistors cracked out for three pulses and then stopped.

I changed the board into Machine A since I knew that coil had worked faultlessly previously. Nothing happened - no sparks output.

I put the PCB back into the Machine B and applied power and as usual one can hear and see on an AVO meter the capacitor rise to ~ 600 and then click as it discharges and repeats the cycle again.

According to one of your earlier notes the suspect could be the secondary on the main transformer so I have unwound it and gone over it carefully with a magnifying glass and cannot see any evidence of shorting or wire break.

My suspicion therefore lies on the Diac and Triacs. The Diac I am using is a small blue thing (about the size of an 1N4148 diode) the number is Diac  32V, DO-35 from RS components. The triacs are Triac,TO220AB,BTB12-600B.

Whilst generally examining the PCB and applying power I discovered that if I placed just one resistor across the output it would fire and the usual flash and crack of blue erupted. This suggest the Diac is working but, perhaps, not all the triacs. At the same time there is not enough punch to blast three resistors in series.

What number Diac are you using?

Any thoughts??

Dave


 
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 12:36:51 am
Sunday lunch time.

Both machines working. The output from the mains transformer is only sufficient to blow one 47 Ohm 2 Watt resistor. Three resistors in series remain intact.

Chief suspect - the triacs.  If it is these items are they failing then why?

How can seven triacs be switched simultaneously? The answer is expected to be - they can't. How about one big mother triac BTA40-600B  Triac (600V, 40A). OPicture below:-



Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 02:17:52 am
Will buy a very large triac as mentioned above and test it sometime Monday.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on June 02, 2013, 03:05:10 am
Not an expert, but this is what occurs to me at this point.
The 7 triacs is fine, many years of testing has shown them to be a good system. They cannot all switch at the exact time, but so close to it, I have not been able to see any spread on the scope to show that this is the cas or not..

If they fail. it is usually the one closest to the output track,..... rare, but that is the only one I have had fail on two ( of many) boards over a number of years. The triac you picture will be destroyed in a few pulses..... tried them. I even used 150A 1500v scr and triacs, but the seven parallel seemed more robust.

Any diac will do the same job really,  and if a traic fails, it will fail short circuit, and the oscillator will just have a low freq squeal, and not rise, as all the power will direct into the transformer, not the cap.

So, what could be wrong.... check the primary windings connection/s............... are both bifilar windings connected, or has one been lost. This would account for losing half the output. It cannot be the triacs as I see it. They either  run, or they are short....no  in betweens.... ditto for the diac... never seen one blown so far.

Try another cap, in case there is a loss of capacitance..... else try the other transformer. The device is so simple, I can't find a complicated answer for you.

Big storage...... going to big low impedance tranny......... makes big spark.... simple really, so it must be either storage, or the transducer. The triacs will dump all the energy they can, only the small toroid and the two caps on the transformer primary can make any difference. The fact that it was viscous for the first few sparks, means the toroid seems to be not too restrictive...... so really means cap and tranny are the only ones left..... just can't find it in me to blame the triacs I'm afraid.... been wrong before too...




...................oztules
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 03:31:29 am
Oztules.

Thanks for the note - all read with great interest.

I took the Machine A ETD coil apart this morning to examine it - seems okay, and then re wound it for 500 turns. I also put in some thin magnet paper between the primary and secondary as there is adequate room.

Try another capacitor - will do, everything is worth a second test at the moment.

One 47 Ohm output test resistor on its own still produces a heck of a large spark and flash to the point where the mounting board seems to recoil.

How about the weather? Temperature here is 32 C and the humidity is at 65%.

I wonder if the spade type connectors are insufficiently contacting between male and female?

When you test with 47 Ohm resistors how many in series do you use?

Dave



Title: Re: Electric Fence Zapper
Post by: oztules on June 02, 2013, 04:46:21 am
I use 1, 2, or 3 in series for fun... or a 470r.   500 ohms impedance is the a fairly normal standard for fence tests.... medium load from grass build up etc.

Without a fence current/voltage tester it is hard to gauge what is actually happening. The resistors arc, and carbon up. They can give spectacular pyrotechnics, or just zap, it depends on how the carbon deposits and breaks down.

A smallish spark, can also be due to a low impedance high current  path(>40A) and so pull down the voltage, or big sparks with not so low impedance, and so current may only be 13 or 20 amps, and voltage stays high (>6000-8000v)... so it is hard to quantify by just the looks. The power may be similar, although the lower the impedance of the spark track, the higher the reactances in the tranny, and power output will suffer more with this combination.

 The more iron in the tranny, the better... even though it is saturated, but  the resistor sparks will vary ... sometimes rapidly as the breakdown path changes. After a while, they seem to settle down in a particular pattern.... however the physics arrives at it, will depend on more variables than I can ponder.

......oztules
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 04:58:04 am
Another hour head scratching and thinking.

Both machines seem to have insufficient power stored to zap three in-series resistors. When I have finished with a machine I always short down the capacitor with a test lead and resistor to ground for safety. Previously when the Machine A was working fine I could always hear the small crack and see a small flash as as the resistor touched the capacitor connector. Now when I short out I don't see or hear these.

Your comment "Any diac will do the same job really,  and if a triac fails, it will fail short circuit, and the oscillator will just have a low freq squeal, and not rise, as all the power go will direct into the transformer, not the cap". 

Machine B oscillator has a healthy growl to it whilst Machine A is quiet - almost silent just a slight whine - apart from a tick every second or so. 

Enough for Sunday!

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on June 02, 2013, 09:11:06 am
"I could always hear the small crack and see a small flash as as the resistor touched the capacitor connector. Now when I short out I don't see or hear these. "
This is a function of where in the cycle you stop the machine.

At first you just stop it well after the last spark... and your a bit unused to the rate......so the caps are near full, and go splat.....once you get used to the rhythm, I suspect you now naturally turn it off just after the last spark, and at this point, there is no charge in the cap to discharge...... simple to check, measure the cap voltage before you discharge with your lead. Now turn it off just before you expect a spark, now you will see 500-600v, and it will have plenty of yelp.

In short, I think it is a familiarity breeds contempt thing, not electrical.

"Machine B oscillator has a healthy growl to it whilst Machine A is quiet - almost silent just a slight whine - apart from a tick every second or so.  "
This is purely a function of how the ferrite mates to the other ferrite..... dribble a spot of super glue into the ferrite interface, and it will all go silent. It is the physical interface of the ferrites that make the noise, and a very slight movement of the ferrites in relation to the former... which is loose around the ferrite.... but a drop of super glue will silence the both of them.

You may not have a problem to solve yet, it may be as previously stated, that it is working fine, but you can't measure it. I have thought that some of the ones I made were weak just as you have.... until I measured the current and the voltage, and changed my mind...... I may also have mentioned.... every one of mine were different in behavior,...... no two the same.... but all in the same ball park.



............oztules
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 04:36:58 pm
Oztules,

After thinking about it all night .............

Both machines work, both have the same performance on one resistor. Observation - seems not to have enough power energy to zap 3 series resistors. Conclusion - am putting 600 volts into a 450 v AC rated capacitor. There may be some internal damage to the capacitors, it is after all these things that hold the energy.

Will buy a new pair later this morning.

Regarding the noise from the oscillator. As an experiment I purchased different ferrites. In Machine A they are 525 uH - the quiet machine. In Machine B they are 3,800 uH (noisy machine) , this must account for something.

Will post in a few hours.

Dave
Title: Re: Electric Fence Zapper
Post by: oztules on June 02, 2013, 04:59:44 pm
........ 450vac is 630vdc... rectified and filtered.... so caps are fine voltage wise...... try 2 in parallel, this should increase the current, and double the pulse time
All my caps are 450vac, and they last for years and years.

These caps have a physical isolating layer (plastic/paper etc)... I suspect there is a fair margin built into the rating as well.

It maybe that your power transformers are over wound for the core size, but i suspect that they are working pretty well. If you can get a measurement tool for the job, you will get a better idea.


................oztules
Title: Re: Electric Fence Zapper
Post by: rossw on June 02, 2013, 05:38:21 pm
Conclusion - am putting 600 volts into a 450 v AC rated capacitor. There may be some internal damage to the capacitors, it is after all these things that hold the energy.

sqrt(2) * 450(Vrms) = 636V(peak)
You are still comfortably within their specification (and that's neglecting ANY safety margin)


To what has been mentioned previously - quantifying the output. Do you have a CRO?
Preferably a DSO or one with long-persistance phosphor?

If it were me (it's not me!), I would set up a simple test, and it would go like this.
1. a CAPACITIVE divider to measure volts. Some HIGH VOLTAGE caps, something like 10pF for the "high side"
and perhaps 10nF for the low side (low side won't need to be high voltage), will give you a 1000:1 divider.
So 20KV to the "hot" side will give you 20V to feed to your CRO. You can measure the rise time, pulse width and peak voltage this way.

2. an inductive loop CURRENT sensor. Basically, make a CT. If you wound say 1000 turns of fine wire around a core, passed your high voltage output (via suitable high voltage cable (sparkplug lead?)), and put a burden resistor across its output, you should see 1mA for every 1A in the "primary". Choosing a suitable resistor (10R lets say) would give you 10mV out per amp in the primary.

Between them, you should be able to see the volts and amps at the same time, to quantify the output.

Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 05:44:31 pm
Am catching up on what I proposed to do on Saturday last.

The following details set out the technical parameters of both machines:-

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 11:03:24 pm
Just tested a brand new 450v AC 50uf capacitor.

The result is exactly what happened with the very first test of machine B.

All connected up, new Capacitor in place, output lead connected to a necklace containing 3 x 47 Ohm 2 Watt resistors in series. Power on and instantly for the first 4 pulses sparks fly out of the resistors.

Thereafter no more spark emission from the 3 resistors. Disconnect test necklace and insert one used 47 Ohm resistor between the output wires and there is much cracking and sizeable blue sparks from the resistor. In other words the same results seen during other tests on both machines.

Then to satisfy curiosity I replaced the 3 resistors in the test necklace with another new set and the results are the same as written above.

I then cut out one resistor and left two in the test necklace and heavy sparks flew out of both for a couple of pulses.

The conclusion is that both machines seem to be working fine. The way the resistors react might be due to different batch production, damage done internally that affects the way in which the current flows or does not flow, humidity absorbed due to outside storage and so on.

As you said Oztules it may be a non problem.

I note Ross' comments about an oscilloscope and I do have one - given to me many years ago. I will dig it out and see what I can do to set up the circuits mentioned by Ross. I may need some help and guidance as I go along.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 11:40:41 pm
I mentioned in a previous note that I had made a new bobbin for Machine B.

I have since made a better second one which is almost a clone of the first except that it is built with intelligence. The second bobbin shown below is a jigsaw construction in that the centre core pieces are fashioned with what can be described a mortice and tenon joints. The material is 1.5 mm thick fibreglass sheet which is easy to saw and file. The ‘long’ pieces are wider than required and each end contains two ‘prongs’ that prevent the main side walls from slipping off.

This second bobbin will be fitted with a 1.6 mm diameter 9 turns of two-in-hand primary, followed by 200 turns of 1 mm secondary and will eventually be retro fitted to Machine A.

Good fortune seems to be on my side. The transformer I purchased from a local scrapyard a few weeks ago has provided the laminates for the first bobbin and as luck would have it countless cuts with hand shears has provided the laminates for the second. Photographs below

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 11:44:19 pm
Here is a photograph of Machine B.

The capacitor is mounted on a mini gantry over the printed circuit board which significantly reduces the size of the mounting board. The PCB is identical to that on Machine A. Only the main transformer coils differ slightly between the machines - details in an above post.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 02, 2013, 11:56:36 pm
I mentioned in a previous note that I had spent some idle time playing around with the layout to achieve 9 (not eight) and 12 Triac PCB layouts. At the same time I included everything else I could think of to produce many options. In the main these are:-

Spade connectors or conventional wire connections to and from the PCB.
A clip on heat sink for the TIP 31 - if its there it can be used.
Proper sized holes and space for the large diodes.
Numerous options on the number of triacs needed.
Jumper holes to connect 'live' triac tabs (A2) centre leg to the PCB next to the toroid. X marks the triac   for the multiple jumpers.
The planes have been chamfered. 
Heavy duty triacs with spade connectors could be connected if necessary.

What have I missed?

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 04, 2013, 03:54:15 am
Hello Ross and Oztules,

Thanks for the note on test circuits.

I plan to follow this up.

I do have an oscilloscope model Hitachi V-212/211 CRT – a gift of old and I have never used it. Bandwidth DC to 20 MHz. Sensitivity  1 m/V/div

I plan to obtain the various parts in your note and then draw up the circuits, perhaps you could shroff them over when they are ready.

With regard to the 1,000 fine wire turns on a core, can you confirm a ferrite rod 100 mm x 10mm would be okay, and will each layer require a paper separator?

What would be the Watt value for the 10R resistor?

Dave in HK
Title: Re: Electric Fence Zapper
Post by: rossw on June 04, 2013, 05:36:57 am
I do have an oscilloscope model Hitachi V-212/211 CRT – a gift of old and I have never used it. Bandwidth DC to 20 MHz. Sensitivity  1 m/V/div

The pulses *MIGHT* be hard to catch on a CRO of that type - purely because of the low repetition and short duration.
That's why I indicated long persistance phosphor or DSO.

Quote
I plan to obtain the various parts in your note and then draw up the circuits, perhaps you could shroff them over when they are ready.

Sure.

Quote
With regard to the 1,000 fine wire turns on a core, can you confirm a ferrite rod 100 mm x 10mm would be okay, and will each layer require a paper separator?

A core is probably irrelevant in this context. I'd wind an air-cored coil you can pass a decent insulated conductor through.


Quote
What would be the Watt value for the 10R resistor?

Well, lets assume it makes 400 amps peak.
At 1000:1 you can expect 400mA in the secondary.
400mA through 10R = 4V and 1.6W. But for a poofteenth of a second. A 1/2W resistor should easily manage that.
Allow some safety margin if you like, use a 1W :)  I doubt it'll even get detectably warm.
Title: Re: Electric Fence Zapper
Post by: David HK on June 04, 2013, 05:45:07 am
Thanks Ross,

Very helpful guidance. The CRO is the best I can do, its worth a flash in the pan for a try. I don't know anyone with a DSO.

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on June 04, 2013, 07:12:08 am
Very helpful guidance. The CRO is the best I can do, its worth a flash in the pan for a try. I don't know anyone with a DSO.

If you get the triggering right (should be fairly easy, it's a nice big step-change in input), and turn the brightness right up and do it somewhere in subdued light, you might be able to see it well enough...
Title: Re: Electric Fence Zapper
Post by: madlabs on June 06, 2013, 09:56:18 am
It never ceases to amaze me how many nice folks you meet on the internet, if you hang out in the right places like this forum. As y'all may remember, I started this thread because I have a bear I need to keep out of my garden.

David in HK has sent me one of the machines he built! And refused to take anything for it! Dave, folks like you make me think there is hope for humanity, you built it for the puzzle of it and then gave it away.  I'm a guy with more projects than can be done in a lifetime, and having one knocked off the list is huge. And this was one I had to get done before fall, when there is a lot of honey and fruit in the garden.

Not only that, but he sent amazing documentation, parts, etc! As I told him, my docs usually consist of a couple of coffee stained pages of scribbles. His work is truly outstanding and the machine itself is beautiful!

Thanks again Dave! I'll post up some pictures of it installed and ready to teach a bear a lesson!

Oh, I do have a digital scope. Just a cheap USB one, but it works. To be honest I don't have time to catch up on this thread this morning, but I'll of course be happy to test whatever whenever the machine gets here.

Jonathan
Title: Re: Electric Fence Zapper
Post by: madlabs on June 06, 2013, 10:03:13 am
OK, I took a sec to scroll up...

I have the high voltage caps needed to make the divider. I have some 50kV wire as well, better than spark plug wire, it's copper. The coil might be a problem, my winder is still misplaced after a move. Might be able to salvage the coil from a solenoid or relay though.

Jonathan
Title: Re: Electric Fence Zapper
Post by: David HK on June 06, 2013, 04:56:22 pm
Not forgetting Oztules who is the brains behind it all.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 12, 2013, 10:02:34 pm
I am still in the process of searching for and collecting components for measuring voltage, wave form and amperage. While that is going on I have also been engaged in searching for lighting equipment that will indicate when the electric fence wire is ‘live’.

After two days trawling the Internet some success has been achieved.

Firstly, electric fence manufacturers such as Gallagher, Patriot, et al do offer warning light accessories that clip onto a fence wire. Some seem to be powered by the pulses and others will only activate when there is no pulse present. Other kit contains battery power. Trying to find recognizable circuit layouts for this kit has been wishful thinking so far.

I then turned my attention to motor vehicles and in particular ignition wires for which there is testing kit. Most of this is associated with engine timing and I eventually found several circuits that looked promising.

The circuit components are fairly easy to acquire but the main difficulty is with the ‘pick-up’ which usually surrounds the ignition wire. Commercial timing guns feature a clamp which contains a U shaped ferrite with x number of turns of magnet wire. The opening aperture for the wire can be covered by a sliding ‘door’ which also contains a ferrite to make the thing box shaped. I can’t find any of these items locally so I decided to make my own.

Fortunately YouTube contains a video from someone who has been down this road already so please view the following URL:-


The chap also has a web site which contains more detail:-

http://www.howtoalmanac.com/kevin/projects/automotive/timinglight.htm

Trying to find a suitable ferrite that can be cut up for the purpose proved impossible so I rummaged through my odds and sods coils box and dug out two pieces that seemed suitable for the job. Another coil was deprived of its fine wire winding and the first U ferrite contains many turns which were not counted at the time. The second ferrite – the E shaped one - contains 150 turns.

Along comes testing time and Machine A is set up as is the test circuit. Most things that I build always fail first time around so I was not imbued with great optimism. The ferrite was placed under the ‘fence wire’ and the machine turned on and lo and behold the test circuit red LED showed a small flash in tandem with the machine pulse. The red flash was difficult to see so I recalled the comment in the video where the speaker recommends a high brightness LED. Later in the day I made the changeover and the difference is spectacular. A nice bright white flash.

Human curiosity being what it is, I then moved the ferrite from under the ‘live wire’ to test the operating distance and found the following:-

9 inches (230mm)         No perceptible signal to trigger LED

8 inches (200mm) to the wire itself                    An ever increasing signal with proportional LED brightness.

I then tested this in circle form using the ‘live wire’ as the centre and found that the test circuit would work anywhere around the ‘centre’. The non-working and working distances are shown for 9 inches and 8 inches above which are the radius of circles.

Car ignition leads   Tested on a Mazda 323 which appears to have HT coils for each plug –             ferrite adjacent to the wires with corresponding bright LED flashes. Maybe detecting adjacent ignition wires but it does work.

This was interesting and as far as I got in the afternoon.  It therefore seems that the output of Machine B at X voltage and Y amps will send out a pulse that has an energy ring of approximately 16 inches (406 mm)  in diameter around the wire itself. Perhaps readers can tell me more about this.

My next test will involve a long run of insulated wire including ‘connectors’ to represent ‘gateways’ that occur in fences to see if the same energy circle runs through the wire at a greater distance.

I mentioned earlier that I found other circuits during the search and here is another that I plan to build – follow the URL:-

http://www.sportdevices.com/rpm_readings/

I have converted some of the circuits into Express PCB Schematic files so they are available for easy and clear printing. If anybody wants them in soft format let me know when all have been tested and reported on.

Comments welcome.

David in HK

Title: Re: Electric Fence Zapper
Post by: rossw on June 12, 2013, 10:41:29 pm
David, I hope this is drawn wrong:
(http://www.anotherpower.com/board/index.php?action=dlattach;topic=731.0;attach=2375;image)

As presented, your coil and cap are purely a capacitive pickup, feeding whatever is detected straight to the gate of your FET with just a small diode clamp to save it!

It would also explain why you're picking up signal inches away from the wires. (You shouldn't!)

The pickup coil should be HIGHLY selective and ONLY pick up current flowing through the core. I think if you look at your source material again, the other side of the coil and cap should go to ground.

Since it's acting now as a CT, you probably should also have a burden resistor across the input. The value will depend on the number of turns you have on the coil. This type of sensor is designed to detect *CURRENT* in the line, not the presence of voltage across it. (A fence "alive" detector should be detecting voltage, not current)
Title: Re: Electric Fence Zapper
Post by: David HK on June 12, 2013, 11:21:27 pm
Ross,

This is what I followed:-

I can easily change things around as you suggest:-

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on June 12, 2013, 11:36:22 pm
Ross,
This is what I followed:-

For a number of years, I specialised in servicing, repairing, calibrating and training people in the correct use of engine analysers (amongst other things). Accredited service agent, with all the circuits of all their equipment - I can only say that regardless the source of that diagram... it's WRONG.

It is working purely as a capacitive pickup. It would do just as well with a piece of insulated wire of similar length.

Properly constructed, putting the plug lead through the U core but NOT CLOSING THE CORE will result in barely enough signal to detect. Closing the core and it produces highly repeatable, low-noise output proportional to the current flowing in the lead.

Indeed, it is my experience with these devices that lead me to suggesting the capacitive divider to measure volts, and the inductive loop to measure current - because both are tried and true methods of doing so.

Just did a quick google for a similar circuit - this is "fairly typical" of a crude hand-held device.
http://www.tradeofic.com/Circuit/4558-IGNITION_TIMING_LIGHT.html (http://www.tradeofic.com/Circuit/4558-IGNITION_TIMING_LIGHT.html)
Title: Re: Electric Fence Zapper
Post by: David HK on June 13, 2013, 01:10:14 am
Ross,

Did you view the You Tube URL mentioned in my post ....

That's where the circuit came from.

Here are some other pick ups .......... 


Any views?

I am not actually out to measure voltage at the moment. All I want to sense is whether or not the fence line is active. Am I up the creek?


Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 13, 2013, 01:17:22 am
Here is a capacitive version

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on June 13, 2013, 01:31:28 am
Ross,

Did you view the You Tube URL mentioned in my post ....

Yeah, and he still got it wrong :)

I watched the video frame-by-frame everywhere I could see the board, but there wasn't enough detail to see where BOTH the conductors went. I bet he built it right, just documented it wrong.

Quote
Here are some other pick ups .......... 
Any views?

Both of those should work for their intended purpose.


Quote
I am not actually out to measure voltage at the moment. All I want to sense is whether or not the fence line is active. Am I up the creek?

My view is that you want to DETECT A THRESHOLD VOLTAGE even if you don't want to actually quantify it.
The coil system you are currently working on is simply not suitable for this purpose.

It's great to measure when there is a spark.
It's great to measure the current actually flowing during the pulse.
BUT.... if you have 10 metres of wire around your vege patch to keep the yetties out and it's all nicely insulated, this thing will generate virtually no output UNTIL something contacts the wire and ground causing current to flow.

Your original circuit is close to the mark for your purpose - but ditch the inductor. Instead, put a capacitor from ground to the diodes, lets say 100nF. Now you want to sense the voltage from the hot wire. Something like a 47pf cap would give you around 2000:1 divider ratio (so a 20KV pulse should give you about 10V input, which should be clamped by the zener). This cap could be:
 * a 47pF HIGH VOLTAGE CAP RATED TO AT LEAST WHAT YOU THINK YOUR OUTPUT IS connected to the bare fence wire itself
or
 * a high-voltage insulation wire, suitably capped at the end to prevent flashover, wrapped several times around the bare fence wire. How many times will depend on the insulation type, thickness and wire conductor size. If you have a DMM that measures capacitance, just wind on enough turns to get around 50pF
 * A metal clip that you can clip over the INSULATED wire section of your energizer output.

Hope this helps....
Title: Re: Electric Fence Zapper
Post by: David HK on June 13, 2013, 01:45:35 am
For clarity I am not trying to measure volts or amperage, I am aware of your earlier recommendations and and am working to obtain the various parts.

Just now I rolled out the entire length of my extension power cable along my street and then connected it up to the main transformer output.  I reconnected the capacitive circuit you noted to be  wrong to a battery and walked down the street testing for a pulse at undetermined intervals. Sure enough it picks up the pulse which is exactly what I want it to do.

I don't understand why you write that its wrong. I do not need to know how much current there is in the line - just that the line has an active pulse in it.

Dave
Title: Re: Electric Fence Zapper
Post by: David HK on June 13, 2013, 01:47:16 am
Our notes crossed over - will do what I can to follow your update.

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on June 13, 2013, 02:29:32 am
Here is a capacitive version

This is a lousy design. Honestly, where do people get off with this sort of stuff??
I'm not going to pick on several particularly poor choices they've made, but what I WILL point out is the reason I really hate it, and why my suggestions (above) were as they were.

Capacitors, as you know, have an "equivalent" resistance at a particular frequency. So a 1uF cap for example, if given a 1KHz sinewave will behave much like a 159 ohm resistor. Change the frequency to 10KHz and it looks like a 15.9 ohm resistor.
The circuit, as shown, is a capacitor (formed by the wire in the plug lead as one plate, the insulation of the plug lead as a dielectric, and the metal clip as the other plate). That's fed to a resistor (and the SCR gate), with absolutely no current limiting). Lets assume the clip forms a capacitor of 100pf (just for convenience).
Lets say the sparkplug is firing at just 20 times a second. Some would say 20Hz, 100pF, 79 megohms.
So we have a divider with a 20KV spark, 79M resistor to a 3K3 resistor as the divider.
We should get about 835mV out. Might just trigger the SCR.
The reality is, a spark has a VERY fast risetime. To the capacitor, it's going to behave more like 100KHz
At that frequency it's looking more like 16K. 20KV and you're going to get something like 3.4KV at the divider (because the resistor is still 3K3). The 1N4148 is facing the wrong way to clamp it, the SCR gate will need to. While the pulse is short, there's a lot of stress on things.

Using a capacitor+capacitor divider, both caps will see the same "signal frequency". Regardless of the pulse risetime, the divider RATIO will remain the same. This is true for R+R and C+C but not R+C or C+R dividers.

Title: Re: Electric Fence Zapper
Post by: David HK on June 13, 2013, 02:38:05 am
Ross,
I think there has been a misunderstanding here.

I am not intending to plonk this capacitance sensor on a ‘live’ wire non insulated electric fence. It struck me that the pulse from an electric fence machine was similar to that in a car ignition system and there may be some occasions where a simple piece of test equipment was required to test the output albeit in the form of a pulse. One could equally test for voltage with other equipment.

I am fully intending to follow your recommendations to test for amps and volts, but the first problem I have is to obtain the parts. 20kV capacitors are almost impossible to find locally except perhaps in a scrapyard but 2 and 3 kV capacitors are around in various shops.

For the 1,000 turn coil action is in hand to make a coil bobbin, but if you could indicate a wire size that part of the project could be accelerated.

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on June 13, 2013, 03:41:28 am
Ross,
I think there has been a misunderstanding here.

I am not intending to plonk this capacitance sensor on a ‘live’ wire non insulated electric fence.

Yes, but when you "make" a capacitor from a wire wrapped around your (insulated) wire - you're making a capacitor. If the wire insulation is good for sparkplug voltages guess what? You've just made a 20KV+ capacitor!

It doesn't NEED to be a device manufactured as a 47pf/20KV cap if you can MAKE one :)
Title: Re: Electric Fence Zapper
Post by: David HK on June 14, 2013, 03:04:12 pm
Reference you last note.

I will make one.

Give me a while to get things organised, but before I commence construction I will show you a proposed circuit layout so that you can advise accordingly.

Dave
Title: Re: Electric Fence Zapper
Post by: madlabs on June 18, 2013, 02:02:41 pm
Whew, a lot to catch up on in this thread. A quick question or two...

So when Dave's zapper arrived, it didn't work. I tested the output transformer by putting 3VAC into one side and seeing what came out the other side, which was 4.75VAC. So I unwrapped the transformer but didn't find any obvious damage.

Anyway, to the question: Think I can get away with using .55mm wire to rewind it? I have a bunch of triple coated polyimide wire in that size from my HV days,

Jonathan
Title: Re: Electric Fence Zapper
Post by: David HK on June 18, 2013, 05:33:22 pm
Ross,

I am about to start making up the 1,000 turn wire coil.

You mentioned previously:- 

2. an inductive loop CURRENT sensor. Basically, make a CT. If you wound say 1000 turns of fine wire around a core, passed your high voltage output (via suitable high voltage cable (sparkplug lead?)), and put a burden resistor across its output, you should see 1mA for every 1A in the "primary". Choosing a suitable resistor (10R lets say) would give you 10mV out per amp in the primary.

Could you please offer me an idea of wire size # so that I can finalise bobbin width and height.

Dave
Title: Re: Electric Fence Zapper
Post by: rossw on June 18, 2013, 05:42:49 pm
Could you please offer me an idea of wire size # so that I can finalise bobbin width and height.

Well, I mentioned 1000 turns only because it makes the maths easier.
Given the current in the (secondary) is quite low you can use wire thats pretty much as thin as you are comfortable using. That stuff thats thinner than human hair can be pretty hard to work with! I really don't think it's anything to be too hung up on. I wouldn't use anything heavier than 28 gauge, I'd probably use 30 or 32 gauge if I were making it myself, but even finer should be ok.
Title: Re: Electric Fence Zapper
Post by: madlabs on June 21, 2013, 12:23:35 pm
Dave,

Well, drat. I rewound the transformer today and while I am getting a little more out of it than before it is still not right. I should have replaced the primary as well. Now the input voltage drops to 1V and I am getting 6v out. So better than before but I am guessing that I damaged the primary windings, as I had a higher primary volatge last time. And I thought of replacing the primary but didn't have quite enough appropriate wire.

Oh, and the transformer that I am using to feed the transformer is an old filiment transformer and rated for 15 amps. It only dropped from 3.3VAC to 3VAC last time, so the primary must be toasted.

Back to the drawing board,

Jonathan
Title: Re: Electric Fence Zapper
Post by: oztules on June 21, 2013, 03:46:22 pm
Johnathon,

I have not ever tried to use a sine wave into this kind of tranny before. Remember it has very low impedance, as the magnetic circuit is rubbish. I am surprised the 3v dropped so small, I would have expected the primary to look like a short circuit of very few milliohms to your source transformer.

The trues wave form is a spike pretending to be up in the millions of hertz.... it has a very fast rise time to protect the innocent....
What exactly did the unit so when you fired it up, did it work then fail, are you getting the 600v in the cap, can you hear the oscillator.. I doubt the traqnsformer primary will fail.. it is fencing wire ...

What part of the fencer didn't work.


...................oztules
Title: Re: Electric Fence Zapper
Post by: madlabs on June 21, 2013, 04:37:16 pm
Oz,

I am getting 600VDC or so at the cap. I hear a whine when the unit is running and looking at a scope with the probe placed near the unit I can see a 5kHz beat.

The transformer is a beefy sucker, weighs > 10 pounds and is rated for 30 amps but I am pulling from only one side of the winding.

I just tried the re-wound transformer and the result is the same - It winds up but no destruction of resistors.

Thanks for the help!

Jonathan

Title: Re: Electric Fence Zapper
Post by: David HK on July 08, 2013, 02:42:16 am
Ross,

I am moving forward again but would like some assistance from you please. I have converted your text into a schematic to show - an inductive loop CURRENT sensor - have I got it right? The bobbin is now made and I hope to add the coil winding this week.

JPEG below




Dave
Title: Re: Electric Fence Zapper
Post by: rossw on July 08, 2013, 03:02:26 am
Ross,

I am moving forward again but would like some assistance from you please. I have converted your text into a schematic to show - an inductive loop CURRENT sensor - have I got it right? The bobbin is now made and I hope to add the coil winding this week.

As pictured is pretty much as described - except there's no way your moving-coil meter is going to respond quickly enough to be any use. Attaching your CRO there however, you should be able to see the spike. Since it's a 1000:1 transformer (the insulated fence lead passes THROUGH the coil, just to be clear) you're going to get 1mA in the coil for ever 1A in the output. And with a 10 ohm burden resistor you should see 10mV for every 1mA, so your output should be 10mV/A.  (so if you see a spike of 500mV, that's (500/10) = 50 amps in the fence wire.

It will be AC, so you may see a negative spike followed by a postive one (as the field builds, then collapses) or you may see a positive spike followed by a negative. Connect whichever way makes more sense to you. (probably easier to trigger on a rising edge spike)
Title: Re: Electric Fence Zapper
Post by: David HK on July 08, 2013, 03:14:02 am
Okay,

That's most helpful and I can follow that.

I may be able to produce a result by the end of this week, otherwise it will be next while the wife and daughter are in Australia (Sydney ~ Jackson Harbour area).

Dave
Title: Re: Electric Fence Zapper
Post by: elval on July 17, 2013, 03:39:22 pm
Please what is the power consumption of electric fences
Title: Re: Electric Fence Zapper
Post by: David HK on July 18, 2013, 01:55:14 am
Elval,

Please go to Page 8 in this thread and scroll down and you will see a typical record for voltage and power consumption drawn by the machine mentioned in this narrative.

Other electric fence machines may well differ for many reasons.

David in HK
Title: Re: Electric Fence Zapper
Post by: WooferHound on July 18, 2013, 08:19:35 am
Please go to Page 8 in this thread and scroll down and you will see a typical record for voltage and power consumption drawn by the machine mentioned in this narrative.

hmmmm . . . there is not a Page 8 available yet . . .
Title: Re: Electric Fence Zapper
Post by: David HK on July 18, 2013, 03:25:01 pm
How do you work that out Wooferhound?

This is Page 12.

Individual thread entries do not have a sequential (#) number, otherwise I would quote one.

David in HK
Title: Re: Electric Fence Zapper
Post by: WooferHound on July 18, 2013, 03:36:33 pm
double hmmmmm . . . I see this as page 7 and your last post was reply #173 as indicated just to the left of the date it was posted
Title: Re: Electric Fence Zapper
Post by: tomw on July 18, 2013, 03:39:55 pm
How do you work that out Wooferhound?

This is Page 12.

Individual thread entries do not have a sequential (#) number, otherwise I would quote one.

David in HK

How many "pages" is related to browsers and forum settings so "page #" may only apply to individuals and their settings, etc.

Just saying.

Tom
Title: Re: Electric Fence Zapper
Post by: David HK on July 18, 2013, 03:41:00 pm
My apologies - you're right about date and # thread entry number - its 04.41 hrs here and I have not quite woken up yet.

However, the mystery is why your seeing Page 7 and I am definitely seeing page 12.

Any thoughts?


Dave
Title: Re: Electric Fence Zapper
Post by: WooferHound on July 18, 2013, 10:01:25 pm
It's interesting that there  are over 175 posts in this thread. and I show it has rolled over to page 8.
I looked very closely at my Profile settings and can't find a selection for Posts Per Page or something similar.
In the beginning of this forum I remember a discussion about increasing the number of posts per page and it was decided to do it. Something like making it 18 instead of 16, and it was done, but it should have been the same for everybody. I don't know why we are seeing different page numbers ?
Title: Re: Electric Fence Zapper
Post by: MadScientist267 on July 18, 2013, 11:37:36 pm
As Tom pointed out, its related to your personalized forum settings...

Under "Profile > Modify Profile > Look and Layout > Messages to display per page" (click for a clearer image, setting is toward bottom of the page):
Title: Re: Electric Fence Zapper
Post by: zartoop on November 07, 2013, 12:59:02 am
David HK,

You are to be seriously commended for all your work and "thinking out aloud" on this project. I want to build this circuit (or a mod of it) and can't thank you enough for what you have done (with lots of help from oztules).

Would you be kind enough to post here your final schematic/s and PCB layout/s. Express files would be great but jpgs will suffice. Your final circuit on here is the 13th April one but you did make some changes afterwards so your help would be appreciated. Thanks!

Cheers
Tony
Title: Re: Electric Fence Zapper
Post by: David HK on November 07, 2013, 02:36:55 am
Tony contact me direct at      strltdATnetvigator.com   change the obvious.

Can you down load Express PCB software because its free. I can then send you all of my files. I have one or two variations but this is only to make the best use of board space.

Look forward to your e-mail


Dave
Title: Re: Electric Fence Zapper
Post by: frank on January 13, 2014, 12:26:29 am
[attachimg=1]Helo.Thanks unto this forum.Ma excuse google translator.Nu know English.
Title: Re: Electric Fence Zapper
Post by: Wolvenar on January 17, 2014, 04:41:25 am
Looks like nice work so far Frank,
Did you have a question ?

Also please post both in english and your native language.
We may have someone able to translate, or maybe we could use a few translators to get its meaning better.
Title: Re: Electric Fence Zapper
Post by: frank on January 24, 2014, 11:00:56 am
Helo. Please tell me transformator HV housing dimension.T.Y..scuze me... google translator!!
Title: Re: Electric Fence Zapper
Post by: David HK on January 24, 2014, 09:17:29 pm
Frank I have attached JPEG's with dimensions of various parts of the Bobbin. The drawings are in AutoCad format and I have had to convert them to JPEG so the resolution is not so good. If you cannot read them please let me know.

The material used is fibreglass sheet about 1.5mm thick.

Hope this helps.

If you have AutoCad software I can supply the files direct if you prefer
Title: Re: Electric Fence Zapper
Post by: David HK on January 24, 2014, 09:29:24 pm
Here are two other bobbin photographs - the cores are the same dimension in both. Only the length and width is different. The grey bobbin is 150 x 110 mm and the brown bobbin 130 x 92 mm. Followthe dimensions for the larger bobbin as shown in the previous post.

Dave in HK
Title: Re: Electric Fence Zapper
Post by: David HK on January 24, 2014, 09:34:27 pm
I forgot to mention that the rectangular side slots are to allow ingress of the two-in-hand copper wires for the primary winding. Not all slots are used - just one for the ingress of the wire. The only reason that there are 6 rectangular slots in each side panel is that they were so easy to make and they also offer choice as to where the start-in wire wires go - personal preference.

Dave
Title: Re: Electric Fence Zapper
Post by: frank on January 25, 2014, 08:38:53 am
Helo. Thanks a lot, I prefer auto cad files ....Thank you Mr. *DAVID HK*,*WOLVENAR*.......(translator)Assembly work seriously.Ty .
Title: Re: Electric Fence Zapper
Post by: oztules on January 25, 2014, 01:41:26 pm
Nice work Frank.

Hope it works well for you.


...............oztules
Title: Re: Electric Fence Zapper
Post by: David HK on January 25, 2014, 05:24:19 pm
Frank,

Well done so far.

You may well be looking problems with the diodes.  Please read page 8, Reply #108 last paragraph, Reply #109, and note the diodes should be LT 6A4 400V/6A.

Oztules comments refer.

What country do you live in?


Dave
Title: Re: Electric Fence Zapper
Post by: frank on January 26, 2014, 02:17:52 pm
Hello, gentlemen, thanks for the information provided about the construction of the transformer HVMai have a question, please tell me what should be used to control transformer Triacs 7 would not it be easier to just use a single Triac power, 10A? Regards, thanks in advance to all those who will answer me! And two last questions if.What power Energy (Joules) is fitting in this configuration, ie the storage capacitor C1, which has the value 50uf/450Vac? From my calculation is not wrong if it should be about 5, 1 J is correct? And last question, what is the estimated length of active wire (in miles)? The project makes it a colleague who can login on forum.
We are in D2 and D3 are BY255 Romania.The other diodes are 1N4007.I modified a bit and use a transistor oscillator scheme Darlington TIP122, I will show schema
And my country Romania.Sorry for mee bad english
Title: Re: Electric Fence Zapper
Post by: oztules on January 26, 2014, 04:33:48 pm
"please tell me what should be used to control transformer Triacs 7 would not it be easier to just use a single Triac power, 10A?"
No it will only last a cycle or two. 150 amp triacs seem to last for a year or more, the 7 small ones last years. Full short circuited fence will test them over time.

"What power Energy (Joules) is fitting in this configuration, ie the storage capacitor C1, which has the value 50uf/450Vac?"
Assuming you are meaning 450vdc charge with 50 uf then yes 5 joules

A 450vac sine wave capacitor will be useful for 600vdc ( 450*1.4=630v ). New storage is   (600x600x.0005)/2  or 9 joules of storage @ 600v instead of 5 joules at 450vdc

Miles depends on fence load. Low loads will get 80 miles of single wire fence.... or generally about 400 acres with many internal fences of multi wire fence will keep the animals ( cows ) under control. Heavy grass load will pull that distance down considerably.


The flywheel diodes need to have a very very high surge rating.. in the hundreds of amps. The 6A04 David mentioned have 400 amps surge for a 6 amp diode. And two are needed for 800A surge suppression.... and even this may not be enough for a constantly shorted fence.

"I modified a bit and use a transistor oscillator scheme Darlington TIP122, I will show schema"

Anything that oscillates will be fine. I chose the one originally for the least part count, and the toughest low impedance one I knew of... so moisture and environmental conditions will not influence it unduly.

Have fun with it... and don't get bitten.


...........oztules
Title: Re: Electric Fence Zapper
Post by: frank on January 27, 2014, 01:25:01 am
Thank you very much for the answers! Not know if I can find diodes LT 6A4 recommend another type of diodes?
Title: Re: Electric Fence Zapper
Post by: oztules on January 27, 2014, 04:07:10 pm
http://www.ebay.com.au/itm/10-x-6A10-1000V-6A-High-Voltage-Silicon-Rectifier-Diode-/150961780615?pt=AU_B_I_Electrical_Test_Equipment&hash=item232605f787&_uhb=1#shpCntId            plus $1.00 post to Romania

data sheet:  http://www.google.com.au/url?sa=t&rct=j&q=6a10+surge+amps&source=web&cd=9&ved=0CFEQFjAI&url=http%3A%2F%2Fwww.mccsemi.com%2Fup_pdf%2F6A05-6A10(R-6).pdf&ei=M9nmUo76PMuGogT39YLYBg&usg=AFQjCNGYEOnSCth4oqxJQz3ka3uSiIXW0Q&sig2=SFFS--RJbqTIoRUca_7DKQ




..........oztules
Title: Re: Electric Fence Zapper
Post by: frank on January 28, 2014, 01:01:32 am
Thank you very much.
Title: Re: Electric Fence Zapper
Post by: David HK on January 31, 2014, 05:39:22 pm
Owing to my lack of knowledge and training, maybe Oztules could satisfy my curiosity on the following:-

The PCB has a total of 14 Triacs divided into two banks of seven each with its own diac. The bank 'on-line' is determined by a jumper. The logic being that if one set of Triacs fails then another set is ready to go. Would it work?


Dave

Title: Re: Electric Fence Zapper
Post by: rossw on January 31, 2014, 09:58:36 pm
I think it would depend somewhat on the failure mode of the original bank of SCRs.

If they failed short circuit, then no - because they'll just short out the "spare" bank too.
If they failed open circuit, then WHY? Whatever made them fail MAY have taken out the "spare" bank too.

It's a long time since I've worked with those devices, but I believe you can "turn them on" with a rapid DV/DT, which COULD see the second bank triggering simply BECAUSE the first bank triggered.

Finally, if you're going to put 14 on the board, why not just stack 'em permanently? Wouldn't that make it just about indestructable??
Title: Re: Electric Fence Zapper
Post by: David HK on February 01, 2014, 02:51:47 am
Your're quite right on all accounts Ross, my curiosity is satisfied.

Dave
Title: Re: Electric Fence Zapper
Post by: frank on February 03, 2014, 10:41:04 am
Hello.My work.Ty
Title: Re: Electric Fence Zapper
Post by: frank on February 07, 2014, 12:11:10 pm
Hello.I did hv coil and make 5kV. little ,small.thank you.Out as yours?thank
Title: Re: Electric Fence Zapper
Post by: frank on February 20, 2014, 01:30:58 am
Hello.HV coil yours out what voltage?ty(scuze)
Title: Re: Electric Fence Zapper
Post by: oztules on February 20, 2014, 02:52:22 pm
Using modified microwave transformers, and 50uf@600v trigger voltage... about 14000v unloaded is the best I have done
normally don't try for that much.

Loaded for 500 ohm load, about 8000v
9 turns of 2 in hand 1.8mm primary, 260 turns 1mm wire secondary.

Every one I make is different though.


...............oztules
Title: Re: Electric Fence Zapper
Post by: frank on February 23, 2014, 01:22:17 am
Thank you.
Title: Re: Electric Fence Zapper
Post by: frank on February 25, 2014, 12:13:29 am
Thank you.
Hello. Two such coils are connected? Parallel? Ty
Title: Re: Electric Fence Zapper
Post by: oztules on February 26, 2014, 03:05:14 am
In parallel. This lowers the resistance. The lower the primary resistance the higher the out voltage can be.

Lower resistance will allow faster capacitor discharge, faster changing field, more voltage generated in the output

oztules
Title: Re: Electric Fence Zapper
Post by: frank on February 26, 2014, 10:21:34 am
Ok....Thank you ''oztules" :)
Title: Re: Electric Fence Zapper
Post by: frank on March 02, 2014, 08:38:18 am
Hello!We found a problem transformer winding mayor HV.Please tell me which of the three modes of winding drawn in the picture below correct? Picture 3(bifilar parallel-counter wound) I understood that mod.It's right?
Title: Re: Electric Fence Zapper
Post by: oztules on March 03, 2014, 03:07:43 am
I use bifilar parallel/



...........oztules
Title: Re: Electric Fence Zapper
Post by: frank on March 03, 2014, 10:19:30 am
Thank you ''oztules"
Title: Re: Electric Fence Zapper
Post by: st8nme on March 18, 2014, 04:40:14 pm
I have tried  to use microwave transformer the laziest way-just removed secondary winding and wound 9  turns.Do not know the number of turns of the primary winding,but loaded with 400 ohm it gives aprox 6000V.
I know it is unreliable,but is working for a week.
Title: Re: Electric Fence Zapper
Post by: frank on April 09, 2014, 02:07:20 pm
Hello.My HV coil:
Title: Re: Electric Fence Zapper
Post by: frank on May 13, 2014, 12:18:14 am
Hello. SHOW the assembly circuit diagram below. TY.
Title: Re: Electric Fence Zapper
Post by: oztules on May 13, 2014, 05:49:53 am
Frank,
I think your asking for the circuit that i used...... I don't tend to use circuits, I just build on the screen... so I have none.

It is the same relaxation circuit as the battery one, except it has a voltage doubler instead of the oscillator to make the 600 volts. An input resistor and the size of the doubler capacitor controls the charge rate... and thats it.

You can modify the circuit that David did for the battery one.


.........oztules
Title: Re: Electric Fence Zapper
Post by: frank on May 13, 2014, 09:57:39 am
Thank you ''oztules"scuze ( google translator)
Title: Re: Electric Fence Zapper
Post by: Bitlord on May 14, 2014, 11:42:55 pm
Hello friends Thank you all for this excellent project!

that is so essential to use high discharge capacitors! for example this circuit does not use these capacitors, the only thing would not use car coils if not designed for you here

(http://chemelec.com/Projects/Fencer-2/Fencer-2a.png)
Title: Re: Electric Fence Zapper
Post by: rossw on May 15, 2014, 02:44:36 am
car coils

As has been discussed to death, car ignition coils are completely unsuitable for this purpose.
Title: Re: Electric Fence Zapper
Post by: Bitlord on May 15, 2014, 07:43:23 am
car coils

As has been discussed to death, car ignition coils are completely unsuitable for this purpose.

correct it is clear that car coils is not recommended! the question is whether he can adapt oztules coil, and if the circuit is suitable for this if we want to not use capacitoir download if not then you'll get the sufficient jouls

sorry use translator
Title: Re: Electric Fence Zapper
Post by: rossw on May 15, 2014, 05:55:49 pm
correct it is clear that car coils is not recommended! the question is whether he can adapt oztules coil, and if the circuit is suitable for this if we want to not use capacitoir download if not then you'll get the sufficient jouls

Oztules transformer has a very low impedance - necessary to match the fence. In order to maintain a low impedance, it has to have fewer turns. In order to have fewer turns and still achieve the output voltage required, the primary must use a higher voltage.

So in short, the version presented using 12V and a FET simply is not capable of the performance of the units oztules described. The inverter and high voltage is absolutely essential for the grunt required.

While I've no doubt the circuit presented might make impressive sparks a foot away from the coil, I doubt it will be capable of a kick that will move a critter off a fence a couple of miles away. Horses for courses - but low voltage primary just isn't man enough for the job once you get more than a trivial fence length.
Title: Re: Electric Fence Zapper
Post by: radu on May 16, 2014, 01:43:50 pm
Hello friends.Thank you all for this best project electric fence!I realized this scheme by Mr. David and Oztules project but small changes and are very satisfied.
The diodes used are not 1N4007.I used P600k.
I apologize for my bad English.
http://s18.postimg.org/6kf3wtmjt/10376087_722055914517195_6055067267594913786_n.jpg
Title: Re: Electric Fence Zapper
Post by: radu on June 05, 2014, 08:12:56 am
Hello gentlemen.Frends,i want if someone has converted the pdf version for toner transfer pcb it.
http://www.anotherpower.com/board/index.php?action=dlattach;topic=731.0;attach=2283;image
Sorry for my bad english!
Title: Re: Electric Fence Zapper
Post by: frank on July 08, 2014, 05:56:08 am
Hello.My HV. coil....
Title: Re: Electric Fence Zapper
Post by: radu on July 14, 2014, 11:33:43 pm
Congratulation,Feri!Looks good!Especially since you made transformer in conditions unfavorable.
Title: Re: Electric Fence Zapper
Post by: Dario on September 24, 2015, 08:36:38 am
Frank,
I think your asking for the circuit that i used...... I don't tend to use circuits, I just build on the screen... so I have none.

It is the same relaxation circuit as the battery one, except it has a voltage doubler instead of the oscillator to make the 600 volts. An input resistor and the size of the doubler capacitor controls the charge rate... and thats it.

You can modify the circuit that David did for the battery one.


Hi oztules
Can you put some more Data of 240v version?
Layout of pcb, size of double capacitor...
Thanks

.........oztules
Title: Re: Electric Fence Zapper
Post by: oztules on September 26, 2015, 04:19:17 pm
Here are the pics of the screen of the pcb program... where it gets designed from scratch on the run.. so no circuits unless you do one for everyone else.

To get the values up, the screen shot does not fit, so print them out and mosaic them if you have to.

Transformer is from a micro wave. Split open wiring discarded, and rewound as per instructions ... wind it as a HV transformer... ie separate each layer of wire to stop arcing internally.
First part of the screen
[attachimg=1]

second part of the screen
[attachimg=2]

pattern complete
[attachimg=3]

wiring of the power transformer. Ignore the battery step up instruction.... just the top instructions
[attachimg=4]

I may get some finished pics for you later today.


Notes: This is the newer version, and is a trippler. So it can develop 900 volts on the primary of the output transformer... beware!!
The trim pot next to the diac is about 100k.
The 1 and 2 uf caps on the board should be AC types. I find the 375vac ones to be fine.

The 1uf cap at the bottom center is 50v. It won't trigger without this cap.

The neon is anything you can find... just a signal for you, does nothing else.

Transformer terminals are marked.

The storage caps will need to be 900vdc or use 2 x 400vac 20uf or more in series instead. They use the terminals marked cap

On the left are the 240v inputs... marked as active and neutral.

Be very careful, this is a large size fencer, and good for 80km or more of fence... it is not a toy.

The bifilar primary is two in hand 1.8mm wire. The secondary is 1mm wire. It is mains connected, so double insulation of the primary from the secondary is mandatory, and of the primary and the core..

 This is a low impedance fencer, and will develop 250000 watts or more for millionths of a second.... don't be on the wrong end. The pulse won't kill as the duration is too small, but it will sit you down very powerfully...... multiple pulses (getting snared/caught in fence) will probably kill eventually... so DO NOT USE BARBED WIRE IN AN ELECTRIFIED FENCE it is illegal for this reason.

Keep the pulse rate to a second or MORE not less. You need time to get away from the fence if hit. The 680r can be increased for this.
The 100k pot changes the step off voltage, and as such affects the frequency of pulse.


The 900v on the primary will kill. It is both mains connected and 900v as well. Treat it carefully, even if using an isolation transformer for testing.

Unless your competent at building mains circuits, this is not for you unsupervised.

If your only half confident, get some supervision from a competent person. These circuits are  dangerous things, and need to be treated as such.

Always have a 500r 20w resistor across the output in place of the fence to keep extra high voltage from damaging your transformer. Unloaded these will run 10000v or more.

These fencers are dangerous.... yes, but not overly so... example is I am surrounded on this island by thousands of kilometers of electrified fences, so while the warnings are justified, they are not to be feared, but due care and caution is mandatory...... the darn things bite hard.

I have seen wallaby dead in fences around the place, and heard of cows dead in fences too. So prolonged exposure to pulses will kill huge beasts of 1000kg or more. Don't allow yourself to get in that position. Be very wary.

...................oztules

Title: Re: Electric Fence Zapper
Post by: oztules on September 26, 2015, 05:48:50 pm
here are some pics to help

connections to external world

[attachimg=1]

close up of board with connections.

[attachimg=2]

more of the same

[attachimg=3]

Transformer

[attachimg=4]

...............oztules
Title: Re: Electric Fence Zapper
Post by: MadScientist267 on September 27, 2015, 04:13:12 am
That's one gnarly gadget Oz :o

Can tell just looking at it that it's certainly not a toy of any kind whatsoever.

Steve
Title: Re: Electric Fence Zapper
Post by: dalek on September 28, 2015, 08:23:24 pm
Oztules,

Thanks for the above.  The attached schematic now contains your recommended revision regarding the Triacs connecting to the anodes of the diodes.

I expect your bored stiff with looking at this circuit, but would you mind giving it the once over again for correctness.

<<SNIP>>

Dave

I ran up on this thread earlier today.  I want everyone to know that I lost some sleep over this because I just had to read the WHOLE thing.  lol  I'm planning to build one of these, as mean and ugly as I can get it.  Just to be sure, is the schematic/circuit diagram located in this post the final and correct one? 

http://www.anotherpower.com/board/index.php/topic,731.msg7836.html#msg7836 

That link should scroll to the post but if not, it is post number 70 by David HK.   It contains a image of the circuit and is page 8 for default forum settings.  I went backwards through the thread and that was the last image I saw.  I just want to be sure so I don't start a fire or get electrocuted one.   We have wild hogs headed our way and from what I have read, it takes a mean fence charger to educate them.  They may be stupid at first but I plan on them having a college degree after just one shock.  ;-) 

Thanks to all who did a LOT of work on this.  This will be fun. 
Title: Re: Electric Fence Zapper
Post by: Dario on September 30, 2015, 06:40:23 am
Thanks Oztules for all data you share with us.
i already did schematic from your 240v - trippler version and i will post it so you can see if there are errors.
i will also make PCB design in Eagle CAD but it will be similar to yours since you allready manage to put all components and use only single layer pcb.
What kind of insulation did you use to isolate high voltage transformer layers? Mylar,Kapton tape ??

Title: Re: Electric Fence Zapper
Post by: oztules on September 30, 2015, 03:46:32 pm
Standard transformer paper.

Usually get 40 or so turns of the 1mm wire per layer, then more paper etc.

So 5 or 6 layers will get close enough.

The primary is two in hand 1.8.....stay with heavy wire for this, as this impedance is critical for max voltage and power transfer... poor as it is.

This type of transformer has served well over here in marine conditions for a decade or so across  dozens of units... simple and works.
I originally potted the whole transformer in epoxy, but now just do the coil, and spill the rest over the laminates... seems to do just as well.

If your designing your own board layout, keep the cap terminals very close to their driven elements... as the current is intense at those points from the cap to the tranny, and the cap to the triacs. Reinforce the board between the cap terminal and the triacs, and the triacs output to the inductor and out put terminal. You want the triacs to see the current evenly as possible, or the one closest to the cap or the load will fail first... beefing up the tracks works for this.

As you will have found from the circuit, it is the same as the 12v unit, but uses a doubler or in this case a trippler to get the dump voltage.
The little 1uf is there for timing and for current sourcing for the triac/scr. if you remove the inductor, the voltage will rise, but the pulse will narrow and the triacs will be under more pressure. experiment with this if you want to get different results re: RFI and transmission.

The addition of a nano or similar micro  and a mosfet, can easily make it intelligent. .... ie use the fet to switch off the voltage climb where ever you want so you don't have to give the biggest bang all the time.... monitor the output, and the micro can drive more voltage or less voltage to the storage cap depending on fence load... and the micro can trigger at a reliable setable pulse ... without changing components to get the balance between voltage and time exact.

I will get around to this soon ( he said), as for a few dollars we can get a fancy unit as good as the expensive units and better... including voltage read out or led ladder indicator, .so we can see the fence loading at any time, and can set an alarm if the load is getting too high, and needs amelioration... or there is a fence short..... time is the problem.


.............oztules
Title: Re: Electric Fence Zapper
Post by: Dario on October 01, 2015, 12:22:37 pm
Oz. Here is schematic Made from your pcb, when you have time take a Look if you see any mistakes.
After you confirm i will put it into CAD.
Thanks
Title: Re: Electric Fence Zapper
Post by: oztules on October 01, 2015, 04:22:47 pm
The little 1uf 50v cap at the diac is in the wrong place. It must do two things.
1. it helps stabalise the timing of the voltage build up for the trigger to the diac... it is part of the RC timing.
2. the circuit will not trigger unless enough current is available to trigger the triacs.... and the stored energy in the cap has the necessary joules to do this too.

Without the cap in the right place, the 3 x 1m resistors will not have the current available to turn on the triac........, which is current driven... so put it in front of the diac, not on the triac side.
The triacs are now TYN1225  ( 25A 1200v) for the trippler... didn't change the pcb as I don't use it for values generally..... left over form the original doubler of 600v.




..........oztules
Title: Re: Electric Fence Zapper
Post by: Dario on October 05, 2015, 02:08:07 pm
This is after 1 hour in Eagle Cad..
maybee some final touch in design but it is 98% copy of Oztules Pcb design :-)
I am not sure should i use classic laminat like old EI core transformer or go for ferrite stick as main core of HV transformer??
Any sugestion OZ ??
Thanks
Title: Re: Electric Fence Zapper
Post by: oztules on October 05, 2015, 04:29:57 pm
Looks the part I reckon, maybe just thicken up the triac tracks a fraction more... ie more real estate added to the bottom of the board, and thicken up the middle track of the triacs, so there is room for some copper and solder there to the heavy currents it will have.

I like it.

Transformer laminate is the go for the power transformer.. or rusty 4 inch nails etc etc.

................oztules
Title: Re: Electric Fence Zapper
Post by: dalek on October 12, 2015, 04:41:27 am
Question.  I'm thinking of using a 120 volt/18 volt with a 9 volt center tap hooked in reverse to build the 12 volt to higher voltage part of the circuit.  I have a bit of oztules in me and that is one that I have a couple of around here.  Plus, I'm building one for my neighbor who has a heart condition and I really don't want to build a very powerful one for him.   I figure I will get around 130 to 140 volts DC out of this, given a few losses here and there.  With the capacitor I plan to use, 47uf, I figure that will give me about .5 joules.  Given a few losses here and there, about .3 or .4 at the output.  Right now he is using a little solar store bought thing that is around .04 joules or so, already got shocked by it twice.   Anyone see a reason this wouldn't work fairly well? 

Also, I live in the USA.  Is anyone that is able to make the circuit board for a reasonable price willing to make a few, maybe a dozen depending on price, and sell them to me and ship them here?  I'm not in a huge hurry for this.  I'd rather a fellow electronic geek have some fun and make a few extra bucks than to pay out the rear for some company to do it plus they can make a couple for themselves or even others while at it.  I don't have all the stuff to print my own.   I may would want a change or two but I think someone here has already designed one that would work.  I'd like to have as many slots for the triacs as I can for when I build the monster one.  Maybe a dozen or so slots.  As I said, I'm not in a huge hurry so if it takes a bit to make and shipping from where ever takes a bit, that's fine.  I have a paypal account that should gives us both some confidence.  If needed, someone can PM me with the info.   I think David had one with the extra triac slots.

Thanks to oztules and David for all the work done on this.  This is a much better design than any other circuit I have found elsewhere.  Add in that you can customize it to suite your own power needs, it is a awesome circuit. 
Title: Re: Electric Fence Zapper
Post by: rossw on October 12, 2015, 04:46:57 am
For $insignificant you can send your gerbers to any number of people in China and get back a bunch of professional, double-sided boards with silkscreen and through-hole plating and all the holes drilled perfectly... it'll cost you a couple of weeks (if you're like me, that just means you get different projects done).

For what it's worth - I no longer bother to "prototype" stuff using veroboard or even those plug-in prototyping things. It's actually cheaper to design the board and send it off than it is to muck about trying to verboard, and they make double-sided boards, with solder resist and silkscreens and drill all the holes and put the feedthroughs in for about what it used to cost me for double-sided PCB blanks! It's a no-brainer.
Title: Re: Electric Fence Zapper
Post by: dalek on October 12, 2015, 05:18:45 am
I looked around for a company that does small quantities of boards but most were pretty pricey.  I guess the setup is what makes it so much.  Anyway, I have seen a couple on here that would work and thought maybe someone here would like to make a few and sell them.  Maybe even make a few bucks and others may want some too.

I'm a Linux user.  I found some PCB software but so far, I can't figure out how to make it do anything.  It's like something is missing or I can't find the needed parts to make it work.  Years ago, I just designed them myself on the board with those little things you pencil on and draw on with a marker.  Now, I don't even have any etch solution or anything to start with.  Plus, my eyes are not what they used to be even with glasses. 

So, I can't get my software to work.  Designing my own the old school way won't work either.  Best I can come up with, hope someone is willing to make a few and sell them.  Heck, they may find a few others wanting to do the same. 

Of course, I could try those little breadboard type boards.  I have used those before but the currents may be a bit much for that.  The copper traces on those are thin. 
Title: Re: Electric Fence Zapper
Post by: rossw on October 12, 2015, 05:56:43 am
I looked around for a company that does small quantities of boards but most were pretty pricey.  I guess the setup is what makes it so much.

Just as an example.... this is NOT what I'd call a "good example" just the first one I found:
(http://general.rossw.net/tracker-pcb-twoboards.jpg)

(http://general.rossw.net/tracker-pcb-twoboards-back.jpg)

These were $0 setup, and I think $40 for *twenty* of these....



Quote
Years ago, I just designed them myself on the board with those little things you pencil on and draw on with a marker.  Now, I don't even have any etch solution or anything to start with.

Yeah, I used to do boards, and photo-reduction, and create reverse film, and expose, develop and etch, then drill, and you know what? It'd take half a day to make a single board. This way, I can design a board, with very fine tracks if I need them, and silkscreen, and solder-resist, and as many holes and feedthroughs as I want, and just send it off and have them come back all made, cut and done...

Title: Re: Electric Fence Zapper
Post by: dalek on October 12, 2015, 06:19:59 am
If no one else is interested in making me some, I will PM you for a link to them.  That's not bad really.  Still, if I can pay someone like David to do it and him either make a few bucks off it or be able to make a few more for others and really help several of us, I'd rather do that.  I can't even get the software I have to make the layout to send in to get them made.  It may be that David would rather send me the files and me then send them off to be made.  Of course, another member may be willing to do this too.   If I do that and can afford it, I may make some extras for others that want them here in the USA too.   Whatever works. 

I wouldn't mind having a dozen or so, just to have some spares in case I need them.  Given where I live, I may end up building a few of these of various sizes for a friend or two, likely more.  Those wild hogs are working our way and they are hard to teach a lesson about where not to go.  As I posted before, I plan to build me a charger that will take a high school drop out hog and make a it into a college educated critter when it comes to a electric fence. 

I'll see what comes along.  Whatever gets me some boards will be fine with me.  If I can get some to help a few other people to, bonus. 
Title: Re: Electric Fence Zapper
Post by: oztules on October 12, 2015, 06:22:32 am
read this : http://www.anotherpower.com/board/index.php/topic,1088.0.html

the protel pcb is here

[attachimg=1]

Your calcs are wrong, you will fry your little power transformer. 1/2 ( E^2 x C ) is the energy, your 110v is actually 150v X 3 so 450 x 450 x .000047/2=5 joules.... thats a lot released in short time

Read the link above to the story I wrote yesterday, and it has 25uf@640v or 640x640x25/2=5 joules..... look at the figures on the HV tester... way over 100000 watts, over 10000 volts and over 17 amps.... you can do a lot with 5 joules if you try.

Dario in another thread has the eagle pcb too.   http://www.anotherpower.com/board/index.php/topic,731.msg10716.html#msg10716


..............oztules
Title: Re: Electric Fence Zapper
Post by: dalek on October 12, 2015, 07:15:24 am
read this : http://www.anotherpower.com/board/index.php/topic,1088.0.html

the protel pcb is here

(Attachment Link)

Your calcs are wrong, you will fry your little power transformer. 1/2 ( E^2 x C ) is the energy, your 110v is actually 150v X 3 so 450 x 450 x .000047/2=5 joules.... thats a lot released in short time

Read the link above to the story I wrote yesterday, and it has 25uf@640v or 640x640x25/2=5 joules..... look at the figures on the HV tester... way over 100000 watts, over 10000 volts and over 17 amps.... you can do a lot with 5 joules if you try.

Dario in another thread has the eagle pcb too.   http://www.anotherpower.com/board/index.php/topic,731.msg10716.html#msg10716


..............oztules

Thanks for the links.  I found out I can install eagle.  Maybe I can get it to work for me.  It seems I need to check for other threads on this same topic too.  You have more than this one.  ;)

I was planning to use the small transformer to do the step up from 12 volts to the 130 or 150 depending on how well the circuit works.  You know, the small low voltage transformer not the monster output one.  The output transformer I was planning to build that so that it can handle the high voltages.  I read this thread and made mental notes about the need for good insulation between each layer.  You made that clear and others that didn't follow that had problems.  The transformer I was planning to use to convert the 12 volt to the 150 or so should work fine, it's just connected backwards is all, but that as the output transformer would likely burn up in a few pulses as you pointed out.  It may not last that long if it is not well made, which is highly likely.   So, small transformer on the front part of the circuit and a hand made one for the output that can handle all that power.  Maybe I wasn't clear on that part. 

I'm not following the 150 x3 part.  With the small transformer hooked backwards, it should convert the roughly 12 volts to roughly 120 volts AC.   When rectified it should go to about 140 to 150 DC.  My precise math is a bit fuzzy tho since it has been a while since I had to compute this stuff.  It was a rough estimate.  So I'm thinking 150 or so volts and a 47uf cap should be around .52 joules.  Since the cap may not charge completely, it could be lower than that but somewhere close to it.  Or am I really bad off here?   Heck, if it is just .2 or .3 joules at the fence, that's fine.   It'll keep the deer out at least.  Plus, he only has about 1500 feet of actual fence line anyway.  His garden is a bit small. 
Title: Re: Electric Fence Zapper
Post by: oztules on October 12, 2015, 07:25:51 am
The little transformer on the dc fencer needs to be ferrite, not iron..... as an output one it would die yes... you would have to have a lot more current drawn to run it as an inverter style transformer. I use etd49 ferrites ones. for the step up.

The trippler 110vac circuit is where the 3 x 150v came from.. did not understand you wanted to go DC.

.........oztules
Title: Re: Electric Fence Zapper
Post by: dalek on October 12, 2015, 07:57:18 am
The little transformer on the dc fencer needs to be ferrite, not iron..... as an output one it would die yes... you would have to have a lot more current drawn to run it as an inverter style transformer. I use etd49 ferrites ones. for the step up.

The trippler 110vac circuit is where the 3 x 150v came from.. did not understand you wanted to go DC.

.........oztules

So I'll have to find some other project to use those little Radio Shack type transformers for?   Great.  LOL 

Yea, this one I am keeping small and not so high a voltage except in the end at the output.  Hopefully it will be a little cheaper to build and last a little longer to given the lower voltages and such.  Sort of anyway.   Maybe not. 

I tried to open that file trippler.PCB and for some reason, it doesn't load up anything.  Maybe I have a wrong version of software here or something.  As I said before, I'm a Linux user.  I'm not sure what anyone else uses here.  I may try to get this done here if I can figure out how to make one of these programs work and whoever makes the boards can use it.  Otherwise, I'm hoping someone else will help out either making them or sending me files that I can use to get them made. 
Title: Re: Electric Fence Zapper
Post by: oztules on October 12, 2015, 12:38:59 pm
http://getintopc.com/softwares/simulators/protel-99-se-free-download/ will get you a windows program.. it is big ..118mb

 I use protel for windows  (PFW) generally under wine.... but have not seen a download for it. 99se was it's big brother back in the day.

The company is now called altium..

Board manufacturers around the world use it... america is a bit different though.


...............oztules
Title: Re: Electric Fence Zapper
Post by: dalek on October 17, 2015, 04:32:34 pm
Oztules,

I been ordering some components to build this fence charger and studying the schematic a bit too.  I'm uncertain about something tho.  What I read in the text and what I see in some of the pics of what people have built seems to differ.  On the high voltage side of this, or the right side of the schematic, is where my question is.  On the schematic it shows a inductor between the output transformer, microwave transformer for you, and the bank of triacs.  Is that a part of the transformer or a separate inductor to help reduce feedback spikes or some other perpose?  Based on a pic posted here and the diodes placement in the schematic, I'm pretty sure it is a separate inductor but I want to be sure.

Also, David was kind enough to send me the files for the circuit and PCB.  Thing is, I'm Linux only with not even a remote possibility of putting windoze on here.  I may have to go to plan B.  I may see if I can get David to order the PCBs from a China maker and me paying for it.  Ross mentioned that he found one that may can do 20 or so for around $40.  For the trouble, I'd be willing to print a few extras and David keep them.  Anyway, I'm still trying to figure out some easier way but may have to talk to David about this.  I'd prefer them be done by a pro since I haven't made a PCB in ages. 

Rossw,

if you have a link to that Chinese maker you found, I'd love to check into it.  I'd like to see exactly what they need to make them. 

Thanks to both. 
Title: Re: Electric Fence Zapper
Post by: rossw on October 17, 2015, 04:42:17 pm
Rossw,

if you have a link to that Chinese maker you found, I'd love to check into it.  I'd like to see exactly what they need to make them. 

I'm out on the mower at the moment and shearing this afternoon.
There are any number of them out there competing for your business. All the ones I've used simply  need gerbers for each layer (component side copper, solder side copper, optionally component and solder side solder masks, silk screens. At least one layer must have board layout and any cutouts. And a drill file.
Title: Re: Electric Fence Zapper
Post by: oztules on October 17, 2015, 07:30:19 pm
The inductor is separate to the transformer.
The pcb is protel, any chinese pcb maker will take just that file, and do the rest.

The inductor is for wave shaping.

A good transformer is key to making the thing powerful.

I only use linux also. Wine will run most things windows though

................oztules
Title: Re: Electric Fence Zapper
Post by: dalek on October 20, 2015, 12:51:49 am
Thanks oztules.  I was thinking it was because of the pictures others posted but wanted to be certain.  I didn't want to build this thing and it be wrong and not work. 

Based on your previous posts, that transformer is what sets your circuit apart from what we can go buy in a store.  Those always have small transformers, that I have seen anyway.  They "claim" to have power but maybe there is a little trickery there.  ;)

I have Eagle CAD installed, along with several other programs that do PCBs and such and am making progress on putting it in.  I started putting it in and then went digging for a video howto.  After watching a little of the video, wrong, doing it all wrong.  Eagle was telling me something wasn't right which is why I went digging.  I'll start over and learn some more.  This is the first time I did one on a puter.  I usually use a pencil to draw it out and then do the layout by hand on the PCB using those dry transfer etch resist things that Radio Shack sells.  A whole new experience for me. 
Title: Re: Electric Fence Zapper
Post by: oztules on October 20, 2015, 01:47:06 am
This is the 12v version I use now...
print onto A4 plain paper, coat with olive oil, place on Kinsten pos pcb board. expose to desk fluro for 30 mins@ 100mm distance
use lye to develop, and then etch.
 Too simple.

The little transformer is the tricky thing. The coils must be the right way around for it to oscillate.... thats why the tracks don't connect... test and then connect accordingly.

....oztules
Title: Re: Electric Fence Zapper
Post by: David HK on October 20, 2015, 01:53:46 am
Dalek,

What copper thickness do you want? The Express PCB website Help section shows this specification: 

Our laminate is 0.062" FR-4 epoxy glass with 1/2 ounce copper. We plate an additional 3/4 ounce of copper (totalling 1 1/4 ounce), resulting in a copper thickness of ~0.0017". Express PCB Manufacturing Specification.

One could e-mail them to ascertain if they offer other thicknesses.

David
Title: Re: Electric Fence Zapper
Post by: dalek on October 20, 2015, 02:08:46 am
oztules,

That does sound simple.  I have a ink jet printer.  I've read that a laser printer is needed.  Do you know if it works with a ink jet? 

DavidHK. 

I've seen 1, 2 and 3oz boards. I've only used 1oz ones tho.  That is actually something I was going to ask oztules about and try to talk to the PCB maker about too.  Given the current that can be flowing through there, short as it is, I was hoping to get as thick as I could afford.  Copper isn't cheap.  Thing is, I was planning to add some copper wire to the leads of the triacs and the other high current components anyway.  I was also thinking of a double sided PCB as well.  That would give a lot more available surface area for the copper in high current areas.  If a professional PCB maker makes it, they should be able to do double sided with very little problems. 

In the end, I want a fence charger that I can turn on and not worry about but that will also send anything that touches it packing. 

Oh, I'm going to try and make my transformers with a toroidial type core.  It may not work to well but may work better.  Gonna try and see.  ;)  If I live through it, I'll post the results, whenever that happens. 
Title: Re: Electric Fence Zapper
Post by: David HK on October 20, 2015, 03:55:50 am
Dalek,

I found a way around the copper thickness problem on the underside of the PCB.

I used Triacs with "non insulated" tabs. I will put up a photograph if I can find it (or take a fresh one) to illustrate how both halves of the power side of the triacs can be used.

Here we go- look at the photograph and you can see that I have used copper spacers and a bolt to link all the non insulated triac tabs together and then fly a copper wire over to wherever to discharge the capacitor into the coil. You should be able to follow the logic.

Bear with me, I am a little busy preparing for my 67th birthday in about two weeks time.

David
Title: Re: Electric Fence Zapper
Post by: oztules on October 20, 2015, 05:01:57 am
Dalek.
I used to use a laser on transparency.... but the old laser died, and the new one did not do a decent job.

Was given a slow inkjet.... which did black print  properly... so tried it on transparency.....rubbish.... dammit, so use olive oil on A4 white, and got perfect results... totally amazed at the definition.. I do mean amazed... easily as good as transparency... don't know why .... but it is perfect.

Need care with the lye/caustic soda, as the olive oil sometimes masks the green that needs to be removed, but if it is warm, seems to be fine.... don't make the caustic too strong.

Copper thickness is a non issue, as you will need to thicken the tracks in a few places only.... much more than thick copper ever will do.

David shows an alternative well worth exploring... happy 67th David... well done however you got there :)

The C core/ poor mans torroid that is here http://www.anotherpower.com/board/index.php/topic,1088.0.html is very very good as it turn out, light and powerful.



..............oztules
Title: Re: Electric Fence Zapper
Post by: dalek on October 20, 2015, 05:08:38 am
David,

I noticed how you did that before.  I thought that was a neat idea but I thought it was a small pipe cut into short pieces.  That should make a good connection for sure.  It also could serve as a small amount of heat sink too.  Right now, I'm not even sure what triacs I'm going to use.   I remember reading that oztules says a lot of smaller ones work better than a few high current ones.  My plan is to make the PCB so that it can hold say a dozen or maybe even 15 triacs.  That way I can match up the number of triacs with the power the charger will put out.  I plan for a somewhat small one for my neighbor but a large one for me.  He's not used to being around something that bites like a electric fence does.   Who knows what I may build later on. 

No hurry.  Right now, I'm trying to figure out how to make this PCB software work.  I figured out what the "net" does.  It connects stuff together.  ;) 

Oztules,

I may have to get up with you on how to do that later on.  Right now, I got to get past getting this software figured out.  If I get pretty good at this, you guys may have created a monster.  Making the PCBs is usually what stops me from doing things. 
Title: Re: Electric Fence Zapper
Post by: oztules on October 20, 2015, 05:26:08 am
Lots of triacs versus few...... actually it was a fiscal decision... big triacs are in the 90 dollar each range and more.. to220 are in the 50 cent range.... don't take a lot of figuring out.

Heat is not an issue to consider, as the operating load is only about .00001% duty cycle.. so off for a very very long time compared to on... no heat really to consider at all.

Have fun with it... Kinsten have made it easy as hell for roll your own pcb , and the white A4 has made it idiot proof.. transparency was always iffy with my newer lasers... the 12 year old Kyocera one did it fine.


..............oztules
Title: Re: Electric Fence Zapper
Post by: tskamath on October 29, 2015, 03:25:10 pm
My thanks to Oztules, David and other's for a excellent documentation.

wanting to build the zapper but with modification to control max voltage before discharge, i simulated the circuit using LTSpice

the schematic without the output stage, only Inverter 12VDC to 600VDC
[attachimg=1]

the output Voltage
[attachimg=2]

without the Cap the Output is 1KV and with the Cap the voltage reaches 1KV after long time for the 50uFD it takes 3,18 Sec to reach 600V with the Value of R2->2K2 and R3->680.

The Primary inductance is a calculated value (http://powermagnetics.co.uk/calculator) with AL for E34 to be 2440 and AL for E49 = 3700 (without Gap) from datasheet (http://www.feryster.com/polski/e349.php?lang=en)  = 1.41mH and for E49 its calc to 2.1mH. The simulation is using turn ratio of 24 the Secondary Turns is 576 Turns (min 400 max 600 as per design Notes).

if i could get some help, it would be great

1. What is the measured value of L Primary 24 Turns on E34 & for E49. (without Gap..? hope this is also true)
2. Simulation show the Voltage across Cap is 600V @ 3.18 Sec ..? But the Fence Zapper is to Pulse every 1Sec and Diac breakdown is 600V..? hence in the simulation the trigger to the Triac would happen once every 3.18Sec and not 1Sec.

If the Inductance is available, maybe the simulation would be more accurate..? else If I would be the exact Period of the pulse I could trial n error to get the Inductance to match the period.

@ Oztules,

a) in the posting you mention that the R2 / R3 should be lowered for faster charge of the Cap. would you kindly inform do I decrease the R2 (2k2) or the R3 (680).? which is a better option.

b) the current in D1 1N4007 is 1.34Amps.. which is greater than 1Amp Peak rating of the diode, but I guess because its pulses, this should not be a problem..? or should the diode be changed.

[attachimg=4]

c) both the D4 & D3 the max current is 54mA hence David PCB with 6Amp Diode is not necessary and the IN4007 would do the job..?

[attachimg=5]

d) the Power in Q1 TIP31 peaks at 48W.. is this normal.. and the CE voltage is 77V which is below the Vce of 100V for TIP31C but above 60V for TIP31A ..?

[attachimg=3]

Thanks in Advance..

Regards
Srikanth Kamath
http://tskamath.pactindia.com
Title: Re: Electric Fence Zapper
Post by: tskamath on October 30, 2015, 02:26:27 am
Hi,

used TIP35C in simulation and I get the 600V @ 1 Sec.. for the following schematic, the extra diode and zener at the base not connected.

[attach=1]

raises a few more question the
Vb on the Q1 is in -38V
Vc on the Collector exceed the Vmax of 100V (simulation show Vpeak of 104V)
Id1 current in the Diode D1 is 3.4A peak.?

[attachimg=2]

with the diode inserted into the Bias loop and with the zener 6.2V the -ve on the base is clamped to -1.45V .. ??

[attach=3]

[attach=4]
any suggestion / recommendations.. or should i just ignore the simulations..?
Title: Re: Electric Fence Zapper
Post by: tskamath on October 30, 2015, 05:38:51 am
Dear All,

This what I wanted to achieve, control the voltage on the Cap.. pls comment.. and suggest any improvements

[attach=1]

the Output
[attach=2]
Title: Re: Electric Fence Zapper
Post by: Dario on October 30, 2015, 07:06:04 am
Check this out, i think it is ok for this zapper and you can Select voltage output.
http://m.ebay.com.au/itm/100W-Inverter-for-DC12V-to-AC20-220V-Voltage-Converter-/291563787503?nav=SEARCH

There is ac and dc output
Title: Re: Electric Fence Zapper
Post by: tskamath on October 30, 2015, 10:20:43 am
Thanks Dario, I am not looking at the DC to AC but the Zapper itself but with a control to inhibit the pulses, in a 25KM long fence protecting the forest areas, I will be sending a SMS to Remote Control to inhibit the Fence Zapper., so that a single person can fix problem in the fence by inhibiting the Pulse and then shorting the Live Wires for safety.

the present design from Oztules is a perfect fit for me but run up to 1KV on the Cap if the Pulse is stopped. attached the simulated data ( I have adopted the simulation to design rather than physically build and test )

[attach=1]

The Cap are rated for 450V and in the email trail Oztules had calculated and informed that its ok for 600V, so if the Cap Voltage is taken to 1KV then I must use two Cap in series, which has more complex issues and these cap are not cheap.

The modification is to control the Max Voltage on the Cap by providing the feedback, I have kept the simplicity of the original design while providing just a resistor divide.

By the way I also realised that this control can also be used to provide Normal, High & Low Selection provided by Gallagher or Other Energiser in the Market.

If Oztules & other can comment if the Schematic till now is Ok or I have missed some critical issues. It will be a great help

[attach=2]

I will add the second part of the circuit once, I have sorted out the Voltage issue on the Cap.
Title: Re: Electric Fence Zapper
Post by: tskamath on October 30, 2015, 04:14:48 pm
attached the schematic and the simulation, the LTSpice is unable emulate the Trafo due to lack of Inductance values of the Inverter T1 and the Pulse T2.

[attach=1]

the simulation report.

[attach=3]

The pulse duration is a function of Cap Voltage and will trigger when the Cap Voltage is above the ref. set by POT2.

[attach=2]

Pls note Its simulated and not actual measurement, hence would appreciate, if i could get feedback on the functioning and also the inductance values.

One Question, which of the two resistor should be lowered for faster charging.. R2(2k2) or R3(680)

Thanks in advance
Regards
Srikanth Kamath
http://tskamath.pactindia.net
srikanth(at)tskamath.com
Title: Re: Electric Fence Zapper
Post by: oztules on October 31, 2015, 07:49:17 am
Hi Srikanth,
This is a grubby little circuit i made up one afternoon about 8 years or more ago... so it has stood the test of time now in many variants.

I finally had some time to take some measurements for you..... I'm sorry they are no where near your simulation... if your interested in this stuff, you are well advised to build one and fiddle with it, the spice is nowhere near the real world results....... where to start.....

First I guess is the little 1n4007.... no, the circuit uses only a max peak measurement of 46ma using a tip35c, and 30ma using a MJE13007 as the oscillator transistor. The other thing of note is that the 1n4007 has a max peak surge  current of 30 amps... yes that says 30... check your data sheet, they are rated as 1amp continuous peak, 30 amps surge for short pulse duration, and any where in between.

EDIT: reread this.... will check again, but I think I meant 460ma and 300ma... will check later today and get back. Will leave as is until I check it out... it makes sense too, as say .35amps x 12v=4.2w.... for 1.2seconds its about 5 joules used up... inverter is pathetic, so 2.8 joules into the cap is about right. (600x600x.000016)/2=2.88joules or for 20 uf  3.6 joules.. last night it was using 19uf@600v

Edit 2: Couldn't help myself.. went and measured it three ways.
First the DVM in series with the leads...MJE13007 was .34a max reading sampling rate was poor....
second with dvm clamp meter and peak hold.... got it up to .56a on one occasion.
third with 1R resistor in line and oscilloscope... this was different.
The wave was a surprisingly clean saw tooth... maybe 30us long. It reliably peaked at 1.2amps... so... one for the simulation... closer with the scope.

The tip35c ( mostly don't use these now... have hundreds of MJE13007... so use them presently) seemed slightly more maybe 1.3-1.4a.

Average was around the 300ma range. So you could justify the better diode... but I will continue to use the 1n4007 as they have not blown ever in these units..... collectively over 100 years I guess ( across a number of units that is). Thats reliable enough for me.... and the worst that will happen is you will loose the reverse connect protection, the unit will still function normally ( .5 volts better actually).

Transformers:
.4mh for the primary of the etd49 ( 3C80 ferrite core)
.3 henry for the secondary...... don't know if that helps you out.

I fail to see why you would introduce another complicating factor like voltage limit for the caps.. that is taken care of by the trigger.

There is flexibility for setting the time constant and the voltage... it is a simple compromise if you don't want to change components, or if you want to tune it to a specific voltage and specific time constant, then that is a once only thing for each unit.... remembering that the voltage will swing through the day from the solar inputs.... 14.5 in the day, 12v at night.. so needs to be timed for max voltage anticipated for >1.2sec. Simple and less to fail.... change cap and pot setting... simple.

In a rural setting, you don't add sensitive components for fun, bugs and spiders and condensation will get it sooner or later.

However, if you wanted to do something useful with the voltage of the caps, then take it a step further, and use a sense of the output voltage on the fence, and then charge the cap to deliver a certain voltage eg 6000v under all conditions... this would save power on a clean fence, and keep the voltage up better on a heavy fence.... that would be a complication with an advantage that is worth the extra parts.

Main transformer:
Simply... keep the impedance to a minimum... thick short windings will keep the time constant down.... like 2 in hand 2.2mm wire.

I tested three inductors in series with the primary for you to consider.
1 an air coil of 50 turns,
2. ferrite of some sort with 20 turns torroid
3. filter from a computer supply.... maybe 20 turns around a ferrite inner

[attachimg=1]

All resulted in a time of less then 10 us. Your simulation was 400us.

The air core was in the 5us area, the torroid about 8us, and the computer core gave about 6us
Sadly it is not perfect, there is considerable ringing on the spike itself on the oscilloscope.... but dissipates in less then 5-10 us dependent on the inductor used.

This is about what I expected, as if 2-3 joules lasted 400us... then the laws of the universe have been battered to death.

These things( 240v trippler units) I have seen run at 40 amps@7000 and more volts... thats 280000 watts.... and thats output..... probably only 30-40% efficient or less. That was using about 8 joules from memory.. very very roughly, thats 8/800000 or about 10 us... which is in the ball park. Tonight I saw 6500v@13amps... thats 84000 watts for about 3joules.. pencil in the massive losses in the transformers etc, and probably we would see near 240000 watts or about .000012 seconds... so it looks like the losses may be even worse than I suspected.

Remember also, the time constant will change with loading. Those figures above are for a fence with 500ohm loading.. standard measurement point  for these things. If you load it with a very low impedance load.. eg plasma short.. then the time will increase.... markedly.

I don't know how your simulation sees the resistance in the inductors and circuit paths, but time of discharge is very very important to keep the volts up and the time down. Transformer resistance is key to short time periods, as is the lead thickness to the caps etc etc.... keep the impedance down to absolute minimum, and the losses will be a bit less too.

I like how uncomplicated this thing is, and it is well inside the guidelines re time, and timing ... well timing is user settable, and juggling the caps and the pot will do it, or change transistors works too SC4242 MJE13007... and anything else in the junk box will have different effects on the timing and the power draw.

In winter, power draw becomes much more problematic, as the sun hours are so much less intense and duration.

Have fun doing whatever it is that your doing.... but this thing does not simulate very well, as the losses are tremendous, the oscillator is raw and so full of harmonics it is a mess, and the currents are absolutely huge.. burning up a few joules in micro seconds is very lossy.

If your going to run it with no inductor, then you don't need the 4uf on the transformer, and your time will shorten even more and voltage will be crazy without a load ( 14000 volts and more I have seen with no inductor)..... also the shock in the silicon in the triacs seems to be severe in the extreme... and life expectance is reduced accordingly...... dont be doing it unless you have very strong triacs/scrs.


Thanks for the effort.. but not for me..... I may do the variable power part using an arduino perhaps to keep the fence voltage as constant as possible regardless of impedance changing.... dew, rain, grass etc etc etc... but then I would also ditch the oscillator, and go pwm then.... light display for fence power and battery voltage......... once you have a micro on board,..........it just gets to easy to do everything.

Odd how the simulation got no where near anything, in fact orders of magnitude wrong...... I guess thats armchair electronics exposed... you need to see results in the real world. simulation of wildly erratic circuits like this is not their cup of tea by the looks of it.

The little inverter easily gets to 600v in 1.2secs with well lless than  the power estimated by your simulation.... not 3 sec @ 3 amps
The time constants for discharge and wave form even with inductors is magnitudes less than calculated... 5us is easy to achieve, and with bigger inductors still hit 10us... 10 times faster than we need from the looks of it.

So it just works... who knew???

I would just build it as is... it works, it cannot ever run the caps past your set point, so your solving problems that don't exist.... and I have never heard of any one wanting to turn the fence down....never.... they all want it turned up.

Stop your unit with a NO relay controlled by your sms... that way failure will terminate the unit.


...............oztules

Title: Re: Electric Fence Zapper
Post by: tskamath on October 31, 2015, 11:16:08 pm
Dear Oztules,

Thanks for the a full detailed explanation, I once again assure you that I have not seen a simpler circuit than this and It work that is clear from the post of the forum. I had no doubts.. :-) .

I am supporting a NGO which is working with the Govt. Forest Dept to keep animals from straying into villages and destroy crops, You are aware any govt. does not approve any HV systems unless we provide the documentation. Hence the effort to Simulate and Provide the graphs to the Govt. Dept that its safe.

I totally agree with you Simulation way off the Charts.. It's always better to Build and test..

Thanks for the data on the Inductance. I agree you scheme on ensuring the Pulse at the Peak Voltage (600V) on the Cap, is best. But it does vary the period of the pulse depending on the Input Voltage. ie faster or slower charging of the Cap.

If you pls inform which of the two resistors (2k2) or (680Ohms) has to be lowered for faster charging?

Yes, I agree with you that a PMW with feedback would be a great improvement to boost the efficiency of the Energiser at all Load and Input Voltages. but like you said, for Rural and NGO it's better to keep it simple.

"Remember also, the time constant will change with loading." -> this is one area I would want to discuss, as the load decrease from 500Ohms the output is lower Voltage and lower Pulse Duration,

I tested a Gallagher Energiser fitted with a 16uFD Cap with their Smart Fence Tester.

JouleLoad (W)Voltage (KV)Pulse Width
NILNo Load9.60(KV)NA
2.40J10006.10(KV)0.14mSec
2.60J5005.20(KV)0.14mSec
1.8J2504.00(KV)0.09mSec

using your suggestion to keep the "Main transformer:Simply... keep the impedance to a minimum", i rewound the Transformer Primary with Two in Hand. I got the following results ( these values are from the Fence tester device)

JouleLoad (W)Voltage (KV)Pulse Width
NILNo Load11(KV)NA
3.00J10007.10(KV)0.11mSec
2.40J5005.70(KV)0.11mSec

Once again thanks for the excellent design and a simple approach. i will make a couple of PCB and Test it on the field using the Gallagher Measurement tester. shall post the result. (the  Smart Fence Tester device also provides a graph of the readings)

Regards
Srikanth Kamath
Title: Re: Electric Fence Zapper
Post by: oztules on November 01, 2015, 12:52:05 am
Decreasing R3 ( 680r) will speed the thing up.

The variable timing is not an issue really. Set for 14.7 or 14.5 depending on your solar charger for the 1.2sec, and it will always be greater..... safe :) simple is good.
The pulse rate does not vary as much as you seem to fear. It needs to get into the bad range of the battery before it gets to the 2 second mark... and then your more worried about the battery than the unit.

An example I just ran for you.

If we run it at 14.7v, we get 48 pulses per minute  1.3 sec/pulse
If we run it at 12.7v we get  36 pulses per minute   1.66sec/pulse


We can see we are close to opitmal at 14.7v and .3sec slower at 12.7

So if we up the trigger voltage a bit we can move the 14.7v point over to 1.2 sec... or add more C or increase R3... or bit of each... but once done.. tats it.

Make no mistake, there is no practical difference between 2 secs and 1.2 sec as far as deterrence is concerned. With a slow pulse (2 seconds or more) they will get hit sooner or later... and it only takes one or two, and they won't go near it again.. they can smell it ( probably makes the hair in their nose stand up or something), for if it is off for longer than say 15 mins, they somehow know.

You won't stop a running animal no matter what... as a rule, they sense it's presence, and have to have a look.... and they get bitten... they don't do it again for a long time... after that they still sense it's presence, but they know what it means. They will starve to death rather than touching it again if the volts were up over 4kv, and the earthing  was good, and ground not too dry.

If you maintain anything over 3-4kv as measured with the tester.... they won't broach the fence... no matter how slow you make the pulse rate.

I usually run them at 1.5secs or even more to keep the power requirements a bit lower.... and push the voltage up higher to allow for more grass etc. I try to stay below 10000v...usually in the 5-8kv range.`

The power  transformer will be saturated... big time... so a short circuit in the fence will pull the pulse width wider as a rule.. your figures say otherwise, and I don't know why, my scope says differently... may be transformer design, I don't know, but shorts involving arcing seem to push the pulse width up, not down.

Transformer is key to performance.... storing joules is childs play, getting it into a fence efficiently is more difficult.

We need some inductance there to keep the RFI down, as well as give the scr's a fighting chance.

I think thats it.

Good luck with it, this simple design has kept many beasts in their respective paddocks for a long time now.

I'm happy using it on an isolated island in the middle of nowhere, but for around villages and folks that are not used to them.. make sure you do the measurements for pulse width and time .... in the real world.. not simulation... here, everyone has units all over the place, so everyone is fence trained.... including pets.

Sadly I cant give you a pic of the waveform and timing... as my 40 year old scope has no way to stop freeze the frames... it is real time electron beam... and the pulse appears on the 10us/div  screen very fleetingly. I don't expect to get a pic at that speed.... hard enough trying to see it in real time, and figuring the shape and duration.... may try a movie perhaps....

Your test with the Gallagher says .14ms. @ 500ohm load... thats over isn't it?


...... oztules
Title: Re: Electric Fence Zapper
Post by: oztules on November 01, 2015, 01:25:28 am
Tried the camera... nikon... no good... but the lousy mobile phone actually delivered... after 61 frames we got this

[attachimg=1]

Hard to see I know.
Thats a 10us/div. The rise time is very very fast, the drop off is slower... but still around 10us all up for 500 ohm load.

If I increased the load, very little changed... unable to say if it went wider or narrower.... you only get to see that flicker for a fleeting instant once every second or so.. but if you put a resistor on it, that is not big enough, it will blow it up, and arc... when that happens, the wave creeps out to 30us... 20 of which is almost a secondary train of pulses... what I saw last night thinking it was ringing.... and probably is.........but only when an arc is present from testing thus far.

Did not do no load, as my scope might not have survived...... someone else can try that.

Hope that is enough for you... learnt a bit myself too
Title: Re: Electric Fence Zapper
Post by: tskamath on November 01, 2015, 01:47:01 am
"Your test with the Gallagher says .14ms. @ 500Ohm load... thats over isn't it? " true.. but the energiser is a 20 year old..? :-)

I agree, the pulse period of 1.2Sec or 2Sec or any value greater than 1.2Sec  would keep the animal away, the reason for 0.10mSec and 1.2Sec is only for compliance. We had cases where people have blamed death of Buffalo or Cattle on the Fence.. They just love to graze the cattle in the forest.. :-(

Yes for sure will do a field test, I was trying to short cut and get the PCB design from David on EagleCad, unfortunately the file he sent does not open.. some Error on line 1.. Have to get the PCB designed and fabricated.. Will do and post

on the Trigger Cap of .7uFD, my guess is the 3 x 1Meg + 220k Pot + 330k = total of 3.55Meg hence the Voltage on the 3rd 1Meg should be 80V when Vcap = 600V and

with the POT set to 75kOhms would give the 30V diac break down voltage (0.5RC 39.30% of 80V.)

Oztules, many Thanks for all the help and guidance, I owe you many beers.. cheers
Title: Re: Electric Fence Zapper
Post by: oztules on November 01, 2015, 02:23:42 am
"We had cases where people have blamed death of Buffalo or Cattle on the Fence.."

They were probably correct. These things won't kill from a single hit.

BUT if the animal is caught in the fence or wedged on the fence, then these things WILL kill a full grown bull.

It is not through electric shock as normal ( so many miliamp through the heart,)  but total disorientation of the entire central nervous system.... and it does not take long either.

Thats why it is illegal to use these on a fence that incorporates barbed wire or any other sort of wire that could snag a victim... keep this in mind..... plain wire only.

We sometimes get wallaby caught in the 5 wire fences as they try to jump through and tangle.... they die... as will anything else unlucky enough to manage to tangle themselves up in one.

All the newer low impedance fencers will do the same thing, the old high impedance ones... I have not heard killing things.. or doing much good at anything, but the new low impedance ones ones certainly can, and do... not often, but it does happen... so the stories are possibly  true I would expect.



.................oztules
Title: Re: Electric Fence Zapper
Post by: Dario on December 15, 2015, 07:58:40 am
My version of PCB arrived :-)
I ordered in China and payed 30$ for 10pcs
There is only diference in text, in my eaglecad text is not over the capacitor sign and some other text like cap out.. etc is missing
Now all i need is order components that is missing.
I will send info about the rest later
Title: Re: Electric Fence Zapper
Post by: oztules on December 16, 2015, 05:19:35 am
Where did you get them made?.. like the black too.


.............oztules
Title: Re: Electric Fence Zapper
Post by: Dario on December 16, 2015, 12:52:44 pm
Hi oztules
 you can send your gerber files to this mail sales@epegpcb.com with your wishes like: silk colour, text colour, 1layer 2 layer, anything... and they will send you invoice in e-mail when you pay the invoice they will let you now when is done, ussualy 5-7 days and they will send it with tracking number.
PCB's are high quality and great price, this is not my first time doing buisnies with them so maybe they gave me some discount.
also visit them www.epegpcb.com

Dario
Title: Re: Electric Fence Zapper
Post by: Wolvenar on December 25, 2015, 05:27:18 am
Dario
That is seriously cool looking!

Great job between you, oz and all the others making these.
Now I'm wanting to do it.

/me slaps himself..  No bad bad, to many projects already!
Title: Re: Electric Fence Zapper
Post by: bj on December 26, 2015, 08:13:06 am
   That is seriously tidy.  The info, and review of service will be a boon
to many in the future I am sure.
   Thanks for the share Dario.
Title: Re: Electric Fence Zapper
Post by: Dario on December 27, 2015, 08:09:17 am
Hi to all and sorry for delay
Since a lot of members asked me for gerber files i will add them into post.
The pcb is 98% like oztules pcb only i did my in eagleCad + minior change
Notice that capacitor's used for trippler and "snubber cappacitor" i used is pitch 22.5mm because they were available here in Croatia
All "thanks" goes to ----oztules----

I am still waiting for some components to finish pcb but the main high voltage transformer is done and i will send some photo later.
For insulation of transformer Kapton tape + bakeing paper ( double or tripple layers between primar and secundar) were used, it should be fine since Kapton and this paper is high temp ressistance + kapton is one of product  used in transformer production of new generation.

...Dario
Title: Re: Electric Fence Zapper
Post by: Dario on December 27, 2015, 08:16:27 am
Here are some photos of production.
Title: Re: Electric Fence Zapper
Post by: oztules on December 27, 2015, 04:40:33 pm
looks beautiful...... makes mine look primitive :(

Hope you have a decent core for the transformer.


..............oztules
Title: Re: Electric Fence Zapper
Post by: Dario on January 11, 2016, 02:04:44 pm
Hi oztules again, i ve finished the trippler board and it is working but the 680 ohm resistor is overheating very fast, did you ever had this situation?? I am using 3W.

Thanks
Dario
Title: Re: Electric Fence Zapper
Post by: oztules on January 11, 2016, 02:35:34 pm
The 680 used to get very hot, but less then 90c as a rule.... but it should not discolour.
You can use a 5w or more resistor there... I find that I have been doing that for the last few... ran out of the 3w units.

Whatever you put there will get hot, as it dissipates a fair bit of power.

I just lift the resistor above the board so it does not cause any board heat.

If you want, decrease the size of the caps ( the 1uf ones) on the input side, and you will reduce the current draw, and can use a lower value of resistor to compensate.

I use what I have handy... and I had a few hundred 1uf caps at the time.


.......................oztules
Title: Re: Electric Fence Zapper
Post by: Dario on January 13, 2016, 04:18:36 pm
Oz thanks for info, but i think in my case problem is in output transformer. I Read some posts and i did primary 9 turns 2 in hand ( bifilar paralel), and later i found you wrote 22turns 2 in hand ? :-)
I will Do some more winding :-)
Title: Re: Electric Fence Zapper
Post by: Dario on January 15, 2016, 05:29:02 pm
Small update :-)
The HV voltage is without load, in some point it reach 10.4KV
Since i am using dc to ac converter i removed the resistor 680ohm from the main input.
This unit does drain a lot of ampers in peak.
Title: Re: Electric Fence Zapper
Post by: mukptl on March 27, 2016, 09:52:25 pm
please see pic for new layer starting  which ok A or B
thanks
[attachimg=1]
Title: Re: Electric Fence Zapper
Post by: frank on March 28, 2016, 01:28:51 am
B
Title: Re: Electric Fence Zapper
Post by: mukptl on March 29, 2016, 12:38:26 pm
this machine can run without load on output ? (open circuit )
mean without connection to fence wire
thanks
Title: Re: Electric Fence Zapper
Post by: oztules on March 29, 2016, 04:40:38 pm
Yes, but will put a lot of pressure on your insulation in your transformer... try to avoid this situation if possible... or put a resistor across the output ( 500R) to keep the peak volts down, and stop the chance of interwinding shorts in the tranny.... it shouldn't... but don't tempt it either.

I use plan B in your question above, as the potential between wires is the least where the layer wires transit to the next layer


Dario, for battery electric fences, power drain is a significant problem with the design, I had not thought at all about power drain with the ac model, as keeping animals in is more important than power cost.. any cost.....

But a battery needs consideration, so you must be more attune to economy.. if you want to do dc, then suggest you go with the dc version, very very much less power required from the battery

.............oztules
Title: Re: Electric Fence Zapper
Post by: mukptl on March 30, 2016, 01:16:11 pm
Thanks oztules
i have same invert transformer 20 & 500 turn but  with one  primary winding no feedback primary winding
that will work ? can use feedback from secondary winding ?
Title: Re: Electric Fence Zapper
Post by: oztules on March 30, 2016, 03:54:26 pm
Not sure if it will start in that configuration.... If you can get it to start it should work.
It is a VFO, so not sure how it will work over the range..... try it and see.

..oztules
Title: Re: Electric Fence Zapper
Post by: RFburns on April 01, 2016, 06:55:28 pm
 So I have built a couple of these and given them to various people and here is a tip for very long fence runs or if the ground is very dry. RF

For VERY long fences, or VERY dry ground: RG6 Coax makes a nice high voltage capacitor. Make a coil of the coax at some point mid-way of the fence, and connect the centre to the fence, and the shield to ground. You will get between 17 and 18 Pf per foot. Doesn't sound like much, but it will bite ! .A couple of these placed strategically will keep the power up.

A bit crude but cheap and easy.
Title: Re: Electric Fence Zapper
Post by: mukptl on April 03, 2016, 07:41:26 am
Not sure if it will start in that configuration.... If you can get it to start it should work.
It is a VFO, so not sure how it will work over the range..... try it and see.

..oztules
Thanks Oztules and all other
small transformer working well but TRIAC not  triggering
resistor im using R1m R1m R1m pot 250 k R330k amd 1uf cap after diac
the cap near diac blasted and even neon gone with 100R
type and voltage rating of cap near diac ?
use SCR or  TRIAC -part number of SCR or TRIAC ?
Mukesh

Title: Re: Electric Fence Zapper
Post by: oztules on April 03, 2016, 03:26:24 pm
The 1uf should be before the diac. It provides the current to turn on the triac through the diac. 50v will work fine, as the voltage should never rise past 30v before it triggers.

The 330k to ground and the 3 meg to 700v and the cap provide the timing.
Not sure how your providing secondary feedback, so it may be interfering in this part of the circuit, and injecting voltage or a path for the hv to get into your cap line.

You must have a decent cap eg 20uf to stop the inverter driving up to very high voltage instantly, and killing the triacs
Title: Re: Electric Fence Zapper
Post by: mukptl on April 03, 2016, 09:52:33 pm
feedback from secondary was not working then i rewind transformer with two primary thats how its working now
for triggering traic i found one of 1m R faulty i will change it then i will update on it

........Mukesh
 
Title: Re: Electric Fence Zapper
Post by: mukptl on April 14, 2016, 08:14:36 pm
HV transformer starting winding in pic is that ok ?
 calculation of joules to Amp correct?
5 joules Time   0.010 seconds  = 500 watts
500watts at /10000V =0.05 Amps


(http://)
Title: Re: Electric Fence Zapper
Post by: mukptl on April 20, 2016, 05:46:03 am
can ferrite bar used in main transformer core ?
about 25 mm dia 90 mm long
Title: Re: Electric Fence Zapper
Post by: oztules on April 20, 2016, 06:28:11 am
It would work...not sure how well, but it would work.

The big steel ones are saturated terribly anyway, so there will be a fair bit of air coil going on anyway..... but not my first choice by a long way.

.............oztules
Title: Re: Electric Fence Zapper
Post by: lighthunter on May 21, 2016, 07:41:28 pm
My neighbor just stoped over an :'(d had a zareba fence controller in back of truck. After i got through with the frustration of finding my security torx (why???) I got it apart and we found a wire burned apart on secondary of transformer. Easy fix as burn was external with enough room to reterminate. Thats rare usually the wire is burned off or shorted several turns inside core. Anyway wow are they trying to kill the animal now? This thing had a capacitor larger than a motor start cap. I didnt look at the ratings unfortunately but it wasnt electrolytic (white plastic tubular body)so I,m guessing 10+uF at 450v.(edit its 50uF 900v) :'( Thats enough to drop most things that breathe, maybe I need one to keep the coons off my solar panels

LH
Title: Re: Electric Fence Zapper
Post by: oztules on May 21, 2016, 09:52:51 pm
There are about 1000 joules in a mars bar, and assuming 500v storage @50uf.... we get about 6-7joules (1/2 E^2xC).... so it has stored energy  of 6 thousandths of a mars bar.... mars bar much more dangerous maybe. :(

But it is the impedance of the input winding of the power transformer that will dictate the power of the surge ( assuming perfect switching in the scr)...

This means very low impedance will give very very high voltage, as the pulse width will be very very small... so power will be huge ( hundreds of thousands of watts in fact).

If they had an inductor in series with the primary, and a capacitor ( 2uf??) across the primary, then they are both making the life of the SCR much easier, and widening the pulse, and lowering the power.

This yields two things, .... less radio noise, and better transmission characteristics ( less lossy wave, and less spiky). They need to keep within a tight time range to NOT cause electrocution... your heart pulse sending system cant see the pulse below a certain width, so cant cause heart stoppage/fibrillation etc.

Nervous system really sees it though, so it is not safe to cop too many contiguous pulses..... or some other parts of you may shut down.


So yes it will give a wallop, but the winding thickness and length, and the usual in line inductor will keep the voltage down below 10000v.
It won't kill from electrocution, but will kill an elephant if it gets trapped into a string of pulses.

Seen full sized bulls killed by these things. Don't know how long it takes... may only be minutes..... never never use barbed wire near the live wires, and it is illegal here to liven up barbed wires directly... for that reason.

 I use 50uf motor run caps for this also


...............oztules
Title: Re: Electric Fence Zapper
Post by: lighthunter on May 23, 2016, 03:39:19 pm
Wow, thats deep :) I guess i didnt look at ckt enough to notice details of design you speak about. Obviously they have expanded on the design since ive had one open. Used to be just a Diode, capacitor, ujt and scr, transformer, that was it. Your comments make me think about my old man grabbing spark plug wires with engine running to check/diagnose ignition ::)

Thanks much for explaining all that. I had no idea of some of the concepts and reasons.
Regards, LH
Title: Re: Electric Fence Zapper
Post by: oztules on May 23, 2016, 04:38:45 pm
"Your comments make me think about my old man grabbing spark plug wires with engine running to check/diagnose ignition ::)"

The ignition coil spark system is a totally different animal, very low power, high voltage..... as the impedance of the secondary is very high ( thousands of turns of hair thick wire). In the above system, the transformer may have only a dozen or more turns of 1.8mm wire on the primary, and maybe 250 turns of 1mm wire on the secondary.... and is capable of 10000v@40amps.... multiply that out...it is a massive amount of power... there is your 100 mile fencer.

Ignition has different transformer, and no storage.. so the watts can only be the  e^2/R of the primary  so very high voltage at very low current.. eg a 2R primary would give 72watts....probably near the 20-30000v.. so current is ma... not amps.

Your ole man would not relish hanging onto a 200000watt ignition lead more than once...

"Used to be just a Diode, capacitor, ujt and scr, transformer, that was it.".... still is really... but now you can see how it works,

Although usually we use a doubler to get the 240v up to 600vdc.... then dump that into the primary. I use a diac instead of ujt , and a few resistors and cap to time the voltage rise into the storage cap..... when it hits say 550v, diac triggers... etc.


................oztules
Title: Re: Electric Fence Zapper
Post by: winger on January 25, 2017, 02:58:36 pm
Hi,
I want to build this kind of energizer, so I decided to do it step by step, so first I made voltage doubler and after it I made triac trigger circuit but before wind transformer I wanted to test circuit with 500 ohm 20w resisstor. Problem is that circuit do only one trigger pulse. Thats means, that my neon lamp lights down and  after lights up only when I turn off/on supply voltage (triacs trigger only one time). I guess it working like this because of triacs don't closing. I want to know if it is because I don't use real transformer or there is other reasons. This circuit what i made:
Title: Re: Electric Fence Zapper
Post by: oztules on January 26, 2017, 03:27:08 am
I think the 500r resistor is to blame. Your not turning off the triacs/scr. They are staying turned on.

Use maybe 40 turns of 1mm wire in a 3/4inch diameter coil to limit the current instead.

.......oztules
Title: Re: Electric Fence Zapper
Post by: winger on January 26, 2017, 06:52:02 am
Thanks, I will tray
Title: Re: Electric Fence Zapper
Post by: winger on April 24, 2017, 01:49:07 pm
Hello,

I finished my 220 volt version energizer. For testing I only have fence voltage tester with, I think, neon lamps. The higher lamp is rated as 6000 volts. So if I test fence near to it connection to energizer, then all tester neon lamps is burning bright, so there is at least 6000 volts, but after approximately 500 meters, neon lamps burns only till 4000 volts ratting. I thinks problem is with fence earthening. For now I have three one meter long spikes which is placed three meters apart from each other. Maybe someone can tell how to make correct earhtening for this kind of fence. Thanks.
   
Title: Re: Electric Fence Zapper
Post by: David HK on May 04, 2017, 08:40:09 pm
I'm giving away various electronics and in this forum note I want to give away my build of the Oztules electric fence main circuit unit. Its so long since I played with it that I have no idea if it still works.

Anyway its first come first served, just PM me your name and address and I will pop it into the air mail complete with photographs circuit drawings etc.

You will have to sort out the power supply and the transformer. If it does not work bin it!



David
Title: Re: Electric Fence Zapper
Post by: winger on June 01, 2017, 01:43:23 pm
Hello, for now I test my charger at real life, all is quit good, but I have one problem, after some time diac in my circuit always dying and I can't understan why?
Title: Re: Electric Fence Zapper
Post by: VIC on September 16, 2017, 08:03:09 am
Hello, Oztules.

Congratulations to you for sharing so much with so many with generous passion, and to David, Dario, and  tskamath for documenting your fence drivers for the benefit of many of others around the globe.

I have spent the last few nights reading this whole thread hoping to find the schematic for your original 12V DC board.   Although I did find the 12V, DC, board PCB lay-out,  unfortunately, it appears the schematic, with components names and values has not  been posted (There is, of course, the 12V light version you kindly adjusted for Madlabs, which, in turn, was painstakinly documented and reproduced by David), but I have been unable to find the one corresponding to your original 12V, DC board, at full power.  I've tried to draw it from the board lay-out, but I am not really good at it. 

I am writing to you from Central Mexico, where crime rates are skyrocketing.  Entire cities where a few years back was a pleasure living, are now becoming very unsafe, to say the least.  I protect our home with a commercial electric wall top fence, 555 timer  driven and car ingnition coil type powered.  This is what you get here from dealers and installers. But robbers, rapists and other type of criminals are not stopped by these fences. These high impedance-powered fences are not a deterrent anymore.   It appears to me that your 12V, DC driver is perfect for wall top, home protection.  I don't think a robber would want to continue messing with a fence like this after a first shock from your "bull stopper", hanging from a ladder or jumping from roof to roof, especially if he has been properly warned with explicit high voltage signs, etc.   

I would very much appreciate it if you would find a moment to scribble and post the schematic with components and values.  I believe that is the only information missing, as you have explicitly and generously detailed the rest.   Thanks a million in advance for your appreciated help.   

Vic.
Title: Re: Electric Fence Zapper
Post by: VIC on September 16, 2017, 06:05:24 pm
Hi, Oztules!

As anticipated via PM, I am re-posting here the schematic David HK drew a while back (2013-2014) from a lighter version of your 12V PCB schematic you scribbled on paper for Madlabs.  Without trying to make it a time issue for you, I would very much appreciate it if you could just print it on paper and write on it by hand the original values of your 12V PCB board as it is, so that it does not take much of your valuable time.  Thank you very much  in advance for your kind and appreciated help, Oztules.


Title: Re: Electric Fence Zapper
Post by: David HK on September 16, 2017, 09:11:45 pm
These are the values and components that are written down on one of my lists:-

Electric fence machine parts and cost   Quantity
   
ETD 49 coil bobbin w/clips and ferrites   1 set
   
Diodes   
LT6A4    5
1N4007   1
Diac           1
   
Resistors   
2.2K      1 Watt    1
680?    1 Watt    1
1M           3
330K   1
1K           1
   
Variable resistor 330K   1
   
LED green   1
   
Capacitors   
0.68uf       1
2.2uf  630 volts   2
50uf 450 volts AC   1
   
Toroid   1
   
TIP 31   1
   
Triacs BTB12  600B   7
   
Printed circuit board   1
   
Coils 1&2 0.8mm dia primary wire   1
   
Coil 3 0.5mm  dia secondary wire   1
   
Coil 4 1.8mm dia primary wire           1
   
Coil 5 1mm dia secondary wire   1
   
Toroid 1mm dia wire      1
   
Spade connectors   10
   
Stainless steel bolt 3.5mm dia x    1
Stainless steel bolt 4mm dia x    4
Copper pipe spacers                   7
   
Insulation board   1
   
Terminal connector   4
   
Nylon bolts   4

Make special note of the diodes in this list

David
Title: Re: Electric Fence Zapper
Post by: VIC on September 17, 2017, 04:52:21 pm
Greetings from Central Mexico, Oztules and David.

First of all, Oztules, last night I checked and rechecked your comments in the entire text of this thread, and I must say I had wrongly concluded that, because Madlabs' power requirements for his fence were quite low your handwritten schematic, latter dutifully and zealously recorded by David, reflected those low power requirements.  But no.  I was wrong.  It is now clear to me David's schematic (as I just re-posted it yesterday, and dated Saturday, 13th April, 2013) is a full power version of your 12V board. Therefore, my previous request to you of upgrading values in David's schematic no longer applies.  I wanted to make this clear ASAP, so you don't  (or any one else doesn't) waste  valuable time on a redundant task.

Now, thank you David for posting a BOM.  Your special note on the diodes is recorded. This is a great help. It seems that neither I could find a 0.7uF value for C4, but a 0.68uF; nor a 2uF, for C2 and C3, but a 2.2uF.  But I only found that at 3 or 4 in the morning, after a desperate search in the net.  LOL!  ::) I guess it part of the unspoken fee you pay as a applicant apprentice to this guild :P.

Now, to the task of sourcing the components. It's going to be a while from this part of the world, I think...
Title: Re: Electric Fence Zapper
Post by: frank on January 07, 2018, 03:21:13 am
Hi!
I would like to oscillate an etd-49 with an integrated circuit 555 (25khz), what winding should I do? ?
Thank you.
Title: Re: Electric Fence Zapper
Post by: frank on February 12, 2019, 09:01:59 am
Hello.
At etd -49, after the winding is made air gap or stuck ferrite? Th.
Title: Re: Electric Fence Zapper
Post by: frank on June 15, 2019, 08:44:01 am
Hi.
We have the circuit below, but it sounds (oscillates) loudly. The oscillation frequency is not good. What can I do? The consumption is 350mA. Thank you.
Title: Re: Electric Fence Zapper
Post by: radu on June 17, 2019, 04:25:56 am
Hello ,
Dear friends ,electronic engineers ,
I would like to ask who can help me with the file in pdf format at scale 1:1 or layout as PCB for this device ,so I can do my wiring diagram using Pn'P method? Thank you in advance for those who can help me.Sorry for my bad english ,but I hope so you can understand me.
Title: Re: Electric Fence Zapper
Post by: WooferHound on June 17, 2019, 04:46:48 am
Hi.
We have the circuit below, but it sounds (oscillates) loudly. The oscillation frequency is not good. What can I do? The consumption is 350mA. Thank you.

That looks like a DIY transformer. They are bad about making noise at the AC frequency. Needs to be coated in varnish or something.
Title: Re: Electric Fence Zapper
Post by: frank on June 17, 2019, 05:43:17 am
Hi.
We have the circuit below, but it sounds (oscillates) loudly. The oscillation frequency is not good. What can I do? The consumption is 350mA. Thank you.

That looks like a DIY transformer. They are bad about making noise at the AC frequency. Needs to be coated in varnish or something.
Thank you.
Title: Re: Electric Fence Zapper
Post by: rossw on June 17, 2019, 05:49:48 am
Just a follow-up on the "coated in varnish" - transformers are not just "sprayed" with varnish, to quieten them down, they really need to be completely soaked in the stuff. It wants to penetrate the windings right through, so they get all locked solid.
Similarly the laminations (if it's not a solid ferrite core).
Anything that CAN move, WILL move and WHEN it does, it WILL make noise!
Title: Re: Electric Fence Zapper
Post by: frank on June 17, 2019, 08:05:18 am
Just a follow-up on the "coated in varnish" - transformers are not just "sprayed" with varnish, to quieten them down, they really need to be completely soaked in the stuff. It wants to penetrate the windings right through, so they get all locked solid.
Similarly the laminations (if it's not a solid ferrite core).
Anything that CAN move, WILL move and WHEN it does, it WILL make noise!
Hi!
I understand! thank you
Title: Re: Electric Fence Zapper
Post by: radu on July 06, 2019, 04:14:58 pm
Oz. Here is schematic Made from your pcb, when you have time take a Look if you see any mistakes.
After you confirm i will put it into CAD.
Thanks
Title: Re: Electric Fence Zapper
Post by: radu on July 06, 2019, 04:15:42 pm
Hello everyone!
Which can be the minimum and maximum voltage for capacitors 1 uF and 2 uF of this scheme? Thank you in advance.
Title: Re: Electric Fence Zapper
Post by: radu on January 30, 2020, 10:47:56 am
Hello everyone, I made this electronic assembly and it look like in the pictures below. With the chinese converter in operation there are problems, so the scheme need to adjust some values ??of the triplet- inverter module. All the results are remarkable and work, even with a trivial oscillator module on 3 khz made with 555.
Title: Re: Electric Fence Zapper
Post by: radu on January 30, 2020, 10:57:08 am
I will come back with pictures and the version of electronic assembly on 3Khz made with 555.
Title: Re: Electric Fence Zapper
Post by: David HK on January 30, 2020, 05:48:46 pm
Well done.  A nice tidy layout.

David HK
Title: Re: Electric Fence Zapper
Post by: dalek on August 29, 2021, 07:27:56 pm
Oztules,

Thanks for the above.  The attached schematic now contains your recommended revision regarding the Triacs connecting to the anodes of the diodes.

I expect your bored stiff with looking at this circuit, but would you mind giving it the once over again for correctness.

I have a question concerning the variable resistor. What current does this carry? And, if it’s fairly large, is an off-board VR required? If Yes, I need to enlarge the holes for wire size.

Next question. You mentioned earlier that the toroid should be in the supply line. Is it worth thinking ahead and adding an alternative layout into the PCB so that with the aid of ‘jumpers’ and alternative positions for the toroid, components can be repositioned? The time and space is available to do this, but could you give me a sketch or sufficient written detail to achieve this.

That’s about it for the moment. I look forward to your comments.


Dave

It's been a while on this topic.  I ran into issues on my end and haven't had time to work on this in the meantime.  I've got KiCad sort of working in my mind now and am trying to work on a few slightly smaller than Oztules versions of this.  I don't need to kill a cow with the thing.  While working on this, I noticed something odd and can't figure out why it is there.  Between what is coil 3 and ground in Davids diagram is a diode D2.  On the other side of coil 3 is another diode, D3 and allowing flow in the same direction, then connecting to C1.  I get why one of them is there, to rectify the AC to DC for the capacitor to charge, but I'm not sure why the other one is there.  I'm thinking of removing D2 and taking coil 3 directly to ground unless there is a good reason for it to be there. D3 should rectify the AC just fine on its own. 

Am I missing a reason for the extra diode? 

BTW, when I get this done, I may put this on something, thought about github, for anyone to use.  I plan to share all the Kicad files and images of circuit, PCB, parts list, details on transformers and gerber files. 

Thanks.

Link to circuit image.  https://www.anotherpower.com/board/index.php?action=dlattach;topic=731.0;attach=2184;image (https://www.anotherpower.com/board/index.php?action=dlattach;topic=731.0;attach=2184;image)
Title: Re: Electric Fence Zapper
Post by: lighthunter on August 30, 2021, 03:53:21 pm
I see your point. The obvious one is it doubles the reverse voltage rating of D3. Beyond that i cant see how it makes a difference yet there must be an advantage as i see it used in other HV oscillators. For example, this ignition circuit.
Title: Re: Electric Fence Zapper
Post by: lighthunter on August 30, 2021, 03:59:31 pm
I think it plays a role in reducing voltage stress of the more sensitive components to the right of C1.
Title: Re: Electric Fence Zapper
Post by: David HK on August 30, 2021, 04:19:28 pm
Hello, I am David, the original poster of contributions to this article some eleven years ago.

I have since forgotten the exact function of the diode you mention, but please be assured that its there for a good reason for it to be there.

Putting the circuit details together relied on more experts than myself, I think Oztules was one.

When I finished building the circuit it did work - violently with the required result. Don't test an electric fence machine output with ones finger tips!

Keep going with your work because I shall be interested to see the result.

David in HK



Title: Re: Electric Fence Zapper
Post by: dalek on August 30, 2021, 04:50:50 pm
Hi All,

I've read this thread several times.  I started posting a interest about 1/3 of the way in.  I also noticed Oztules hasn't been very active in a while.  I hope he is OK.  I really enjoyed his posts, even tho he calls himself the village idiot. ROFL 

I've built things in the past but not one of these.  I noticed on Oztules' original drawing D2 was there.  That's why I posted.  I figured there had to be a reason for it being there but I had no idea why.  Given that others think it does perform some function, I'm going to leave it in.  I may replace it with a jumper just to see if something blows up but plan to leave it in the circuit.  Oztules put it in the original circuit for a reason.  Maybe he will post his thinking on this later, and let us know he is doing OK. 

Given it has been a while, anyone still using a fence charger based on this that is still working?  If so, post any problems, if any, you had with it.  Any adjustments that may have had to be made. 

My Kicad abilities is minimal.  Right now, it needs some serious refining.  Still, I'm getting there.  I've been looking at seeedstudio.com and pcbway.com for making the boards.  I'm also looking at oshpark.com but can get pricey.  I may try to make my own for the first one, faster and cheaper too.  One thing, I used a ETD49 transformer for the step up transformer.  For a small fence charger, that is to large.  I plan to pick a smaller one before I'm done.  The current one may become a large, just add more triacs, then reduce to a medium and reduce further for a small.  Adjusting the sizes is going to be interesting. 

Thanks for the post.  Glad to hear from you again David.