Electric Fence Zapper

[oztules]

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

[madlabs]

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

[David HK]

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

[rossw]

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)

[David HK]

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

[elval]

Please what is the power consumption of electric fences

[David HK]

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

[WooferHound]

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 . . .

[David HK]

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

[WooferHound]

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

[tomw]

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

[David HK]

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

[WooferHound]

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 ?

[MadScientist267]

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):

[zartoop]

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