Anotherpower.com Forum
Renewable Energy Questions/Discussion => Automation, Controls, Inverters, MPPT, etc => Topic started by: techitout on November 23, 2014, 09:32:42 pm
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4 months light, continuous duty from my powerjack, then, today, I noticed the hum sounded slightly louder, I tapped the case and it went quieter, I then gave it a second tap, it got louder and smoke came out (emergency shutdown carried out).
Mods I carried out were extra inductor for low idle consumption, and bypass voltage sense divider to stop over voltage shut down ( caused by charging voltage spikes? ). I had not yet fitted the temperature gauges to the heat sink, and transformer, and suspect the main fan was not coming on ( the middle one was going on and off as it should ).
I am located in central queensland and it has been 35+ degrees ambient, so maybe heat stress has taken its toll ( I hope it's not the control card causing shoot through, because I don't want to fry another lot of transistors ).
I am currently investigating potential loose connections / shorts and replacing the 20 x IRFB4310 with 24 x IRFB4110
I just thought I should share my experience, and will follow up with results of repair and hopefully a positive solution.
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now for an update ...... the a3120 (TLP250) opto isolators on the control board are U/S, so I can't get the inverter going until I get a couple more (good that they're in sockets). I am now convinced that the front fan has not been coming on and the middle fan just isn't enough to keep the heatsink cool. Also, I am suspecting the assumed over voltage divider is somehow linked to the over temperature alarm and fan fail alarm somewhere in the hardware and / or firmware. I've measured the fet drive signals from the control board on the cro, and bottom bridge signal is getting through to the fet gates, but the top bridge drive signal isn't getting past the opto isolator (bootstrap voltage ~ 15v). but at least it seems to be trying to fire up ... after 15 sec, I get an audible alarm and then shut down, so I'm not too concerned about further damage to the control board......fingers crossed.
Hope this is of help / info to you all with lf power jacks ... cheers
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Just my 2¢ worth... The combination of "tapping on the case" with it "tapping back", and lack of drive on one half... doesn't sit well with me. Fair possibility I'm jumping to conclusions but may be something to it. I'm sure oztules will have a more informed position on it, just thought it worth mentioning that there's seemingly less than coincidence there in my mind.
Regardless of the cause, looks like it was quite a show! :o
Steve
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Thanks for your input Steve, certainly, I welcome anyones input on this. I have gone through the entire inverter with a fine tooth comb looking for potential bad connections or potential shorts to no avail, why should it blow when I tapped it ... beats me, I think the outputs of the opto isolators were taken out when the fets blew, hence now no drive to the top end. New opto-isolators are on the way, so I will find out soon, I am testing on a current limited supply to be safe. Welcome anyone elses thoughts ... I'm still thinking heat, but cannot be sure as I'd been slack and not put the temperature gauges on, but open to others thoughts ..... oztules? .... cheers
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Oh goodness.. I've seen that scene before... usually when i try the battery charging without turning it off before disconnecting... but not this time from your explanation.
Heat ... possible if no fan, but light duty... gee it should have stayed hot but happy.
Over voltage if your charging from solar... the unit can't shut down, and if you go over 65v it will perish.
Most likely, the ribbon connector going to the main board from the control board had a poor connection, and the heat started help the poor connection, and tapping took it over the edge.
They are very tough if the signal does not get messed up..... very very unlikely to over current the thing... but mistiming or losing signal for a fraction of a second is terminal.
the current limited supply is a good idea.... except you have a massive number of UF in those big caps, with a low impedance path to the fets..... that may blow them to hell if there is a cross over of signal... without any supply. They hold a few joules indeed.
Interesting that the totem pole transistors didn't fail.... very odd, I have never been that lucky..... be sure they are working properly before applying power to the main boards fets... you may be seeing driver voltage from the lm339 chip, and not the totem pole drivers.... usually they blow.. unless yours is a 24v system, then you may be ok.
The pwm power supply gives you the high side driver voltage for the high fets, it will be fine if the control card is waking up ( drives the housekeeping too), and the opto gives us good isolation.... and the sockets are a good thing for repair..... except if you have heat problems ... not enough to kill the fets ( >130c for light duty I expect), but enough to cause the plastic to micro- deform in the socket legs... and possibly give us poor connections.... so it is in the connector/s side of things I would be looking at very very carefully.
I have not suffered this kind of unknown failure ( usually doing something stupid) ie from loose wires/connectors, but Graham on another forum was bedeviled by it on a W7 inverter ( same boards essentially).. particularly when he was plasma cutting and welding at the same time. Once he solved that, all was good regardless of load.
.................oztules
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Many thanks for the input oz,
Yep, I was pretty surprised when it blew, I was hoping I wouldn't need to do any repairs like this for a few years yet, but, I guess I'm learning as I go (the Power Star circuits were a godsend).
I've ruled out over-voltage as it was morning when it happened, so voltage around 51/52, besides, my solar reg is pretty tight on tolerance and well smoothed.
I'll be super checking for bad connections on the control to power ribbon.
I'm just hoping that the current limited supply may be the difference between losing 1 leg, and 3 legs of the Bridge, at least until things are all good again. (I only have so many spare transistors)
On the totem pole transistors, I only checked for signal at the gates, so it certainly could be the lm339 o/p getting through a blown transistor, more checks, although, both high legs and only one low side leg was blown, I'll test out those transistors anyway.
I think I'll be building an external temperature proportional speed fan control for this one, I was paranoid about heat, at first, then got complacent, now I'm super paranoid.
cheers ... Dave
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Yes, their algorithm for the fan is confusing and ... well I don't think much of it.
I built a small comparator and driver for the fan/s, and it holds it steady at 38c even at 4kw and more. I have now wired the hot water into it permanently, so at least 2 hrs a day it runs >3kw. Before it would run up to 60c before the fan decided to run.... then drop like a rock to 35c
These things are not perfect, but gee they are a good start.
I would put my inverter up against anything else now for set and forget for running a house... it is just like the grid, turn on anything you want whenever you want with whatever you choose..... but it is big...... real big....,and runs the 15kw main board which has double the heat sink of the normal 8000w... but electrically identical ( no surface mount resistors, but same value through hole ones for the 20k gate resistors.).
Make sure your inductor has no loose connections, and the connections to the heat sinks are tight. The high side fets switch much more slowly than the low side, so should run much cooler. They only switch on and off with each cycle, the low side is pwm... so heat should have affected the low side first due to switching losses not rds on loss...
I'm a sook..... I like obvious faults..... such as why did I drop that screw driver in there?????
................oztules
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I think they forgot to put the algorithm in my one (a friday afternoon inverter in my opinion .. LOL)
Anyhow, the plot thickens (maybe) .......
I have found that the power supplies to the isolated side of the opto isolators have blown the zener diode (shunt regulator)
The question is ... did this cause a shoot through by destroying the opto isolator output / over volting the fet gates, or is it a result of it ????????
The ribbon cable to the power board tests ok and doesn't seem to have intermittent fault (that I can find).
One of the opto isolators didn't seem all the way in the socket, maybe that was the problem, but no heat damage obvious[attach=1][attach=1]
I hate sneaky faults.
As far as it goes, I'm with you oz, these are good value for us diehards, a good starting point for the ultimate flexibility.
Might be time for me to order another board set.
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This might coincide with the adverse reaction to the technical tap????
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the tech tap requires a movement of something... a loose chip would qualify for that .
The zener would require that the gate fused with the drain. This would give you high potential for the zener to swallow...
It should die short, and the fet would likely be destroyed completely.
The fact the zener dies short would suggest the fets blew before the zener, as a shot zener would shut down the fet ( short gate to source)... and that has no consequences that result in death to the fet.
Shame they don't sell just the control card like they did months ago on ebay.
If you contact the seller, they will likely sell you the control card only for about $45 plus $25 post.... they did for me before they went ebay.... better than $179 for the set. 4110 are less than a dollar each. The power card is basically indestructible, just fets and resistors... in fact if you got 2 control boards and postage, your way in front of the dual boards for $179.
.................oztules
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So the PJ lives again (hoorah), though I was a pessimist and have so far only put in 3 fets on each leg to test it (at low load ~ 60w), and can now see a reasonable sine wave coming out the plug hole.
I have replaced the original 8 pin opto-isolator sockets with some better quality items, replaced the zeners on the opto power supply.
I went 18V, just to protect the gates of the fets, and not lower as I first was going to as 12v zeners would have sat there generating heat.
The ribbon cable has been replaced with a 10 pin idc socket (ok, more connectors = more chance of faults, but I had to wreck the ribbon connector to remove and test it anyway, (I hate desoldering double sided boards ......).
The saga of the fan continues, and looks like beneath the hot glue goop, the assembler had put a temperature switch across the gate and source of the fan power switching fet, ensuring that the fan never turned on when it got hot. (source and drain may have worked better).
I am now trying to work out a good strategy for the fan control before putting the PJ back into service.
Oz, your comparator system sounds easiest, did you leave the fan tacho connected to the control board?. ( I think my over voltage problem may have been a fan fail alarm due to no tacho signal from the fan)
I am still concerned about the lower totem pole drivers, and wish I'd ordered them with the new opto isolators, although they did test ok with the multimeter, but they may be degraded and fail at a later time. Maybe I'll just swap 'em anyway. thoughts?
Thanks for your support and knowledge on these PJs, oz, I am learning a bit more about what makes them tick.
I've just bought a 600 x 800 electrical cabinet, so I can rebox the pj and put a few more whistles and bells on it.
cheers
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Nice work there.... the machined sockets are an improvement for sure.
The 10 pin idc is the same as the power star inverters.... should be good, it is in most pc's.
The 18v setting is a good idea, no point in driving the transformer more than necessary.
Yes replace the totems poles if you can. They are almost free those surface mount transistors, and will set your mind at ease.
As you have no charring yet from those, it can be useful to use to92 versions, to stay away from the board surface.
The biggest problem with blowing these up while experimenting, is the burning under the totems.
If your not expecting to experiment, or push them beyond their boundaries, then this is moot. They should not fail under normal operating conditions... but your did...
somehow.
The fan and it's settings are weird... and I don't like them... at all.
I used a small fan from ebay with 3 pin plug to satisfy the tacho needs of the control card.. put i where you wish.....you can see it hanging near the transformer at the top of the pic.
The chip needs to see it or it will shut down the unit.
Then used the 12v output that normally drives the main screen as a power supply for a small comparator and fet to drive the two main 5" fans independent of the board.
The assembler was in error... must have been a Friday thing. On the ones I have, they got it right.... same with pressing in the chip.
Quality control is not their strong point as yet from the looks of it, but it is truly a useful little control card, and you can make a very very very robust unit out of it.... and mostly easy to fix if you kill them from abuse.
Here is a shot I should not share... it was meant to be tidy, but I keep adding bits to it, and it became a scene of total chaos..... I will build a second one with all the additions planned for.. rather than tossed in
[attachimg=1]
It is only 8.30 in the am at the moment, here is the front panel shot... ( really 7.30am without daylight savings)
[attachimg=2]
The advantage of tons of solar panel.... cheap, and even before the sun actually gets to hit them at a decent angle, the batteries are getting a fair shake and are 94% charged... the rest of the day is wasted yes, but even on 8/8 cloud cover days, it still fully recovers by 4pm... including 4kwh of hot water each day ( or thereabouts)
Life is just too easy with big solar and big inverter.... just like on the grid, set and forget..... water the batteries once each second month ( not much at all)
We can see near 1kw of grid tie coming in, so it is running the house, and providing another 500 watts of power into the battery ( apprrox10 amps ) the rest of the 49amps is coming from the48v arrays.... some of which have no real sun as yet... sun is south of east west line, it won't be until 10am or there abouts before it comes north of an E-W line and hits the panels at a decent angle.
A shot of the pv control cabinet made from a aerosharp grid tie box. It controls up to 100 amps or more @ 60v. Simple knob at the bottom left for voltage control.
It is supplying the remaining 40 amps.... yes a new meter and shunt are on the way since the upgrade.
[attachimg=3]
The top temp is the transformer, the lower one is the heat sinks on the low side fets.
The only problem I see with this current system, is the batteries are too big now. Ideally I could get rid of 16 of the t105's, and just run 8 of them, and put the 16 into dry charged storage without electrolyte.... but because I can and do use very high loads, I don't want to sag the voltage, or distort the plates from excessive current.
I believe that with lead acid, it is a case of use it or lose it, so you are best to drive them hard, and fully charge each day, rather than lightly discharge them and recharge fully each day. I don't seem to need three days storage, as with this much solar, every day is a good day... maybe one or two days per year are dark enough to cause concern for a smaller battery system... but the rest of the time, 250ah would be enough to do it.
The super cheap solar changes the paradigm that solar engineers use... but they have not woken up to it yet. Now days 10kw of solar is $5000, and $5000 for batteries and modified power jack, and you have the best system I have seen. Not tracking array, no solar hot water gas fridge or any other RE stuff need be tolerated.
In fact a 15kw inverter built from PJ boards from ebay etc and grid tie transformers is less than $500 all up..... leaving $4500 for trojan t105re's
It is a different world now for sure.... on a sunny day, I probably shed more than 75kwh... total waste... but it costs nothing to do. I design for worst days... not best.
Or I can run a few kw of lawn sprinklers all day....if I had that much water available... power to burn.
...............oztules
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hi guys new to this site i see its not just me that has a blown 8000w LF RIP PJ 29/10/2014 to 4/12/2014..... Is there a teamspeak or a skype where people can talk about there blown up inverters as im bad with typing and most of the time i get it wrong trying to type things that i dont know how to fix sorry to be a pain any help be good as im not get help from the seller
the black smoke smells so bad it going to be there for long time
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If you can do a bit of elecrtickery, then you could replace the 4 driver transistors, and the 2 opto's and the 24 fets and the 24 gate resistors, and it will PROBABLY be fine.
If the driver transistor have burnt the board under themselves, then it is more difficult to achieve this, but doable with some imagination..
If you don't trust yourself to do this, then
http://www.ebay.com.au/itm/repair-parts-main-board-control-board-of-LF-Pure-Sine-Wave-Power-Inverter-/221351354856?pt=AU_Tool_Parts_Accessories&var=&hash=item338991a1e8
Replace wire for wire, and it will be a new machine... perhaps if you tidy up your new wiring, and tighten all bolts to the heat sinks well, be probably better than new.
Quality control is not their strong suit. Not uncommon to have spare nuts and bolts floating around, and the wiring all over the place.
They do wax in the connectors which is probably a good thing.... but they could spend a bit of time doing a lot of things better.... but they are cheap and very reliable when you fix up their loose bits and pieces.... not all are poor, but there is a sprinkling of real doozies that turn up.
The actual electronic design is very good and stable as an inverter only.
.......oztules
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Tapping ......
Gee I believe a Novel could be written on the subject .
I Knew a foreman once taking readings on about a 100 gauges
was never satisfied with each gauge until he had tapped it at least 5 times
Not that I'm against tapping....just saying like in this instance it can be carried to excess .....like Steve said .....If it "taps back" Whoa !
Hope you can appreciate my humor here : )
Norm.
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If you don't trust myself to do this, then... there a problem there is the ban me from buying off them as i give bad feedback so i may have to get friend to try fix it as i never done this kind of work before i have to sit with a web cam with you on how to fix it but i don't think you have to time to do that for a person you dont know and i hate to ask that from you i be a pain sorry
one more thing your not a sales guy from this power jack group are you? as i read your post on it before i buy mine off ebay you mad it sound so good so i got on this one then i see techitout blow hes one and i was thinking gee hope mine dont die like hes did then the very next day mine blow how unlucky am i
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Hehe.... no definatley not a power jack man.... but I do admire the electronics of the board and chip as an inverter.
If you read all the stuff I have written on these things, it will always be.... great inverter, needs a few tweaks to make it MY inverter, but I have told it as I have found it.
I have blown up three or four in the time I have played with them.... never have I blown one from normal use as an inverter, and I have done some grievous things when testing out the original one... It has copped a few repairs, but once when I shoved a chrome temp probe between the mother board and the heat sink... bang....
Then somehow I managed to do it again... as if I hadn't learnt the first time.
But the other two were both when I used it as a battery charger, and when I turned it off.... bang. First time I thought it was dumb luck, second time I'm gun shy from using it in that fashion.
It has been rehoused, bigger transformer, and is being driven way above the power jack recommendations, and has never looked like failing with any load thrown at it. It behaves like the grid, can't say enough good things about the mother board and power board... but only as an inverter. It can run the hotwater, jug, water pumps, and the fridge, 700 liter freezer and tv and wall warts... in other words the house.... and never gets hot even.... happy as hell.
I will never use it as a charger again, or a UPS... no matter what they claim
How did you blow yours up?
I am on an island in Bass Strait, and our "grid" to use the term loosely,is forever dropping out... now I am off grid, that has not happened. Tas Hydro has a tough time with our windy conditions.... so do the trees.
People turned up, so will finish this later.
........ oztules
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wow the bad units you see on ebay they are more peolpe with blown inverters.
The seller relist them then they tell the person that like there money back to send it to the person that buys it. and you have to pay postage for this to hate to see a guy buy it from usa lol
i just got told from the seller they need 3 days to sell my bad unit to sell then the sell the part to who buys it.
i just seen a bad unit go for $153 plus $100 p&h to someone there must be alot of them out there in a AUS just to let you know guys as you guys know how to fix them be ok for you guys you may end up with my blown inverter
or up for sale is my bad unit what i payed for $480 plus you pay postage lol jokes i just like a working inverter this is getting to me sorry to be a pain again i'm not good at this it pays to go in a shop to buy gear so can take it back
oztube it be ok if i give you my teamspeak so we can have a change to let you know how i ended up here thats if you use teamspeak or do you have skype?
I had problem with charging 1st so i stopped using it as one but know i have no inverter would you beleave me that under 100w of christmas lights killed my inverter so a low load can kill them even but i did use it on a aircon for 3 of the hot days we had last week use 888w the most i seen from the aircon and that was only for 3 to 4 hrs each day all i can run for a i dont take my batterys under 12v my solar tracker runs only 3x 200w 12v panels on it so i dont have alot of solar yet.
i love to live on island next door to oztules that way can knock on he door ask for help and hope hes a beer man to have a drink with him
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Is this a 12v unit?
Scary current you have for those voltages. 1kw will be near 100 amps... hope you have plenty of battery...... 8kw = 800 amps..... cant imagine that...
Anyway, not they don't die from low power... or high power either from my experience.... only silliness or turning off grid when in charge mode.
The only other thing I can see is over heat, but thats hard to believe at 100w of chrissy lights.... very unusual.
That leaves poor connections.... quite possible, as I have said many times, quality control is not their strong point. A poor connection can lead to HV inductive sparks in the wrong circuit...
I don't skype or anything else broad band... we have a wet piece of string for an internet connection to the mainland 200kms away.
It it has gone back further than the drivers, your into the main chip, and this is not recoverable..
I have had this happen with a W7 inverter, but it was due to a spider, dying and smearing it's bodily fluids underneath the 20 pin connector... and it then shorted between the 60v rail and the data line, under the plastic connector land.... bye bye W7.....
My experience though is that they really are tough..... but no way would I guarantee PJ workmanship.. but still less than $500 for a 4000w unit is not too bad either....but you need to QC it yourself from the looks.
I notice about 300 for sale on Ebay, and 2 bad ones for sale.....I wonder if that means 150:1 good to bad?? I tried to buy one but missed out a few months back.... They didn't have it as it turned out, and gave me two 15kw control cards instead.... happy me. ( same as all the rest really, but different software set points, and heavier current transformer..... and much much longer ribbons.,.... just saves using current bypass wire to get up in the 8000w mark on a normal board.
...........oztules
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here i found more burnt marks on this little board not sure if i buy the part for $179 o ebay then i still have this to deal with and not sure as cant see any numbers on it all burnt up
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Hi oztules,
I am a mate of Sean above and I am a junior electronics man (even though I am 37 :) ). I am guessing the photo above is the control board and its cooked. How do we check if the main chip is damaged? I am guessing from your statement its not fixable if this is gone.
One of the mosFETS is totally char grilled as well (along with the control board as shown).
Justin.
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Is this a 12v unit?
yes it is 12v i know i know i get it all the time up the volts
Scary current you have for those voltages. 1kw will be near 100 amps... hope you have plenty of battery...... 8kw = 800 amps..... cant imagine that...
i have 5x200ah ac delco all linked with 50mm weilding cable yes i have 1000ah
Anyway, not they don't die from low power... or high power either from my experience.... only silliness or turning off grid when in charge mode.
never did that
hes the thing i 1st got it i had my battery bank down to 12.1v so i said i try the charger out 1st turn it to number 4 on the charger for lead batt then turn it on and seen 2500w on the screen on the inverter thinking to myself thats high hope i dont kill my batteries hope comes down on watts and then the alarm went off and it turn itself off so i let it cool down turn on again and went to 1750w then charge fine then on so i tested it with aircon in bed room run fine used it that night with ac kick in and out next day i tryed to charge again seen 2500w again and over heat and turn off again so i send email to seller told her what it was doing she said was normal to turn off safe mod she said so i got on skype with her with my webcam and show her what it was doing for the 3rd time charger over heat turn of i said it cant be right so i ask for her to ask the tech if it can turn the charger down so it don't over heat and she said she ask and get back to me and never did so i give bad feedback to seller saying (charger over heats they said was normal, stay away) so i new if i use charger it kill my batteries or charger over cook and inverter die so i stop using the charger never again i said so only solar from then on as on the meter on it i used $2 on power so new it not change if i used the power just keep going up i used $6 all up on the meter and stopped working long way off the $480 cost me
this inverter run fine it run washing machine fine 6 loads 360w max and the vacum cleaner fine 2 times 15min each time 2000w max and microwave fine for 3 mins don't rember the watts for that but worked fine the big test for it was my aircon i plug it in and its only 888watts most i seen it get to the fan come on some time then turn off i run it for 3hrs one day then and 4 hours 2 day and about the same on the 3rd day and that's it all plug in one at a time the morning it died the missus put a load of washing on work fine then not used all day was that night i pulled the chissy lights out and one at a time i plug in to see what the watt went up each set of lights and i got to the last set and she stopped working, walk in to see the smoke and alarm going off turn it off as i never seen the smoke like that was thinking it go on fire next so got on ebay next day till seller and she said i have no warranty as i give the bad feedback and there it is sorry long read again
The only other thing I can see is over heat, but that's hard to believe at 100w of chrissy lights.... very unusual.
each time i come under to see the watts on the meter on the screen on the inverter i got up to 80w the fan never even come on thats why i say 100w of light
That leaves poor connections.... quite possible, as I have said many times, quality control is not their strong point. A poor connection can lead to HV inductive sparks in the wrong circuit...
just my luck i get a bad one
I don't skype or anything else broad band... we have a wet piece of string for an internet connection to the mainland 200kms away.
maybe if you like to look at the last teamspeak 2 i still run a teamspeak 2 server and have a solar room there for talking maybe some thing you like to look in to talk with your mates and also all members of this website its real good on net can talk fine on old dial up net so it be fine for all users i also have teamspeak 3 server as will i happy to open them up to all members to your site to chat on inverters and power needs even wind as i'm in to wind generators
all you need is a cheap headset to use
bet you get the wind down there mate i just lost a blade on my 1kw wind gen in a storm last week with 3 solar panels and some of my roof got to fix the wind gen know and this inverter
It it has gone back further than the drivers, your into the main chip, and this is not recoverable..
hope it not that bad
ok i have a mate he alot better at fixing things like this i just fix car motors ,hes better then i am i have to get him to talk with you i say he be doing the work on this inverter to try get it working again as i was just going to buy a w7 and you just put me back again not sure on what to do getting me down or you think a W7 be fine for me long a the spiders stay away from it lol
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The W7 is a much better quality controlled version of the PJ..... but and it is a very big BUT...... the transformers in the W7 do not allow you to bring the idle current down.
On the 48v unit, this means losing around 4amps@50v or 200w or more usually that you don't get back.
On a 12v unit I have not heard what the idle currents are for an 8000w stack of transformer......but it would have to be similar, as the amount of iron to magnetize is the same, but the voltage is lower. As amp turns deliver the magnetising field, so you think you may do better than the 200w... but probably not, as the turns are only 1/4 of the 48v version, so the current should go up to about 16amps... but I have not seen or measured the 12v version.
A story i did here: http://www.anotherpower.com/board/index.php/topic,780.0.html
The relevant circuits are there too.
You will get the idea, that the W7 needs much more in the way of conversion to get useful operation out of it.
The good thing with the W7..... is you do get the power they claim, and the charger seems to work more smoothly... thanks to the lossy transformers I suspect.
They are essentially the same cards, resistor for resistor etc etc. slightly different programming parameters.
I like the W7 as an honest workhorse. If you are going to run it very hard for short periods where the idle won't catch up with you, they are very nice.... otherwise you stand to lose 4-5kwh just turning it on for 24 hours... big big drawback.
I will answer your friends questions on here or Personal Message me when he is in need of advise, but I don't wish to tie myself to the computer for verbal discourse.
If he is a techy, then the circuits on here will give him the help he needs, if he is not a techy type, he will probably not fare too well, as they are intricate on the mother board.... and will need soldering skills of some experience... very fine work, but not difficult technically.
If you run amok, we will see what else we can do.
.................oztules
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Thanks for your help oztules.
The company selling the PJ is being very unco-operative, so playing the threaten / response game at the moment to hopefully get them to send us some spare parts. If that fails then I will pull unit apart and see what seems blown (apart from control board and obvious cooked FET).
I am not bad at electronics, but I don't have the time to learn troubleshooting on circuits. If someone points a finger and says replace that, I can do it. I find analog a bit of a drag actually (although I respect it) its just not for me. I am a programmer by trade, and live in microcontrollers and the minimal circuits I require to talk to A/D devices I might need.
So I know what a transformer/mosfet/resistor/cap/ind/optocoupler etc etc is, but if you asked me to design an inverter - I can't do it. If you asked me to modify one electrically on paper - I can't do it (I could wind a transformer, but don't intend to do that).
Also if its not something simple (like a nut bolt, lose wire, or short etc) I can't diagnose why something would blow up (like this one).
Justin.
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ok Justin, you should be able to handle this then.... it is simple stuff, and if it dosent work, nothing you will ever do will get it to go.... but i expect $30 or so worth of parts will do it.
We are not going to trouble shoot, just replace the active components in the out put stages.
We only need to buy the opto's ( on net)
then the two types of pnp and npn transistors
24 fets IRFP4110 ( less than a dollar each, I just bought 400 for less than a dollar each for a different project ( solar water pumping BLDC motors)
and 24 resistors.. I replace all the fets and resistors on the power board....no matter how well they test.. for the few cents, it is time well spent.
The circuits here http://www.anotherpower.com/board/index.php/topic,780.0.html
Will give you the part numbers for the transistors and the opto ( you will still be able to read that anyway, the IRFP4110 fets and the resistors 51r or thereabouts ( I have heaps of that size... so use it instead of the original 46 I think) the blown surface mounts are the 2sa1213-y and 2sc2873-y ( SOT89)
The little transistors will be the problem, as they have probably burnt the board and ruined it... but if you use a circuit drill to clean it up, you can re-track ( messily) and get it going... or you can use through hole ones, and use the long legs to some advantage.
equivalent through holes are 2sa1020 and 2sc2655... I think , 2A 50v.
After that it will probably work fine again.
Look carefully at where the fet legs go, there may be erosion between the pads the lands.
and thats it.
Disassembly and assembly will cost the most time.
Cut the legs off the fets, and take the legs out independently, and the resistors the same way is easiest by far. Double sided boards with large copper areas are hard to unsolder all at once... even with a sucker I think.
Generally thats all we have to do. I have seen the power supply chip fail, 3842 pwm chip,and some zeners on the high side power supply /s that drive the opto's.They will fail short if they are causing a problem, and test like a normal diode if not. .....
You should be good to go.... darn cheap to fix when you have to.
"
Also if its not something simple (like a nut bolt, lose wire, or short etc) I can't diagnose why something would blow up (like this one)."........... me neither. These things are terribly robust if used only as an inverter..... why that one blew.... I can't begin to guess..... and certainly under virtually no load... check for loose power wiring to and from the transformer and battery inputs.... even the input terminals from the battery, and battery cables to terminals etc etc.... looking for a spike.....
Just remembered, your fets are different... your are only 12v ones... take the numbers from them... irfp4110 are for 48v units... will do 24v too apparently.
...............oztules
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BOOM!
And THAT is exactly the help I was looking for :) The FETs on this 12V one 190A - 80V ones (will get the part number, but local suppliers don't have them). Trying to get something similar. From RS Australia/Element14 the FETs will be around $2.6 for cheapest. Do you the thing irfp4110 would work (180A - 100V) or should we stick with the 80V (I have found a 214A one at this voltage- $4.6 each though!)
I will check the burn out on the control board see how bad it is, but I am handy at fixing circuit boards...the circuit diagrams will definately help here.
Thanks again :)
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the 4110 is probably good enough for your purposes. I thought they had higher capacity ones for 12v
What is the part number they use in yours.
If it's rds on is not much better than the 4110, then that is the way to go.
I bought plenty of those, and the driver trannies and the opto's. If you have trouble sourcing, I can make up a rescue package.......$2.60 is a bit rich for fets when you need 24 of them.... starting to get too expensive just to see if...
I will admit, the current in a 12v system scares the hell out of me... driving huge amps through those tiny fet legs.... makes me shiver.... but I guess they work. For the topology, I think they should not offer a 8000w peak unit@12v... I would limit it to 2kw... maybe 3.... and that is still a lot of amps.
At 48v when I'm using 4000-5000 watts, I am still only in the 100 amp range.... more my comfort zone.... and then still only 6 fets per leg...... looking at the leg wires..... don't know how they survive, but they do.
The 180 amps for the 4110 is the silicon limited amount ( continuous), but the package limit , it is about 120a...(continuous)
Pulsed drain current can be 670amps, and dissipation max is 370 watts. rdson typical is 3.7milliohm... not bad for a 100v device.
we'll look at the spec sheets for yours when you give me the numbers... have not played at 12v before... as you may have guessed.
............oztules
EDIT I mentioned irfp4110... that should read IRFB4110.... the P version is to247 and the B version is TO220... the 247 version is too big physically... my bad.
So look for IRFB4110 not the IRFP4110.
example:.. you will need to cut and paste the whole thing, as the auto thing here will not do the whole address.
http://www.ebay.com.au/sch/i.html?_odkw=irfp4110&_from=R40|R40|R40|R40|R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xirfb4110&_nkw=irfb4110&_sacat=0
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From memory and search on eBay (america) - I think they are RU190N08. $8US for 5 :) much better. So much more on US ebay for this stuff.
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looks like $8 USD for 5units is about 2 AUD a piece....... bit expensive by twice....or $40USD for 25units
They look like 180a 80v 4.5mohm.... looks like the 4110 would do fine.
Can't read the Chinese to see the power dissipation.
However looks like this would do as well at half the price.... 25 units for $29AUD
http://www.ebay.com.au/itm/25-pcs-IRFB4110-FB4110-POWER-MOSFET-Transistor-TO-220-LI-/131191694960?pt=AU_B_I_Electrical_Test_Equipment&hash=item1e8ba26670
............oztules
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i got it apart and to find the red wires lose as if i had of tightened the screw 2 more turns i maybe have a working inverter still hey? here i am thinking i lose my warranty if i looked in side it.
also is this the numbers you guys are after UV190N08R i think and one blow with black smoke burnt up and one just like good it open but not burnt
and the little board burnt up the whit chip don't look in right not sure was see on the new parts
thanks for the help guys Sean......
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Well, looks like you have found the problem... loose wire will do it....
As a matter of course, I replace the tlp350's, the 4 totem pole surface transistors on that board too., ALL the fets and all the fet resistors ( the through hole ones, not the 20k surface mount ones)
I have not worked on the later model ones with a daughter driver board...looks like it makes it interesting.
On the 48v units there is a surge diode that can go , it is obvious which diode that is, it is an add on under the control board... may not be on the 12v one... as it is a 12v surge diode.....
Check the zeners on the floating power supply drive for the tlp350 chips, and you should be good to go.
At least we know what got it.... like I said, they are very very hard to kill when they are running properly as a straight inverter..... I have not been able to thus far.
Disappointing your relationship with the seller stinks.... that is a true workmanship warranty, and they are generally very good with that..... you must have pissed them off bad.
I have never claimed warranty, as I know why I blow things up... but there are a few that have, and been very well looked after.
You could try to kiss and make up, or at least get them to sell you a new control card.. around $45 plus shipping, last I got one. The main board is easily fixable.
Sometimes digging your heels in is not the best way forward.
................oztules
EDIT: Just looked at your pics again... you do not have through hole resistors on the power card.... so you will need 24x 46r or whatever they are surface mounts
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That is a true workmanship warranty, and they are generally very good with that..... you must have pissed them off bad.
yes they do get pissed if you give bad feedback but i did try for help 1st if they only ask me to open it up and look over it when i had them on skype on a webcam show them it over heating and turning off in shutdown so i did try to get help why it was over heating and turning off they said it was normal ter to do that and can give no help as its normal for it to do. why i put the back feedback on as( charger over heats and turns off they say its normal) on the feedback
so i get Justin trying to fix it for me hes a good guy and all you guys are on here you guys help i got no help from seller. just my luck hey , im ment to putting my money back in to fixing my 1kw wind generator back up after a storm took it out . but got to hold off as i have to get this inverter fix 1st
its not easy being green !!!
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Some advice from someone who loves windmills...... don't throw anymore good money after bad with it.
I moved to this island because it was in the roaring forties... just so I could play with wind power generation.
I have built a few wind generators and seen up to 5kw out of one of them.
When solar was $10/watt they were magic machines..... your in Brisbane, you can buy solar at 50 cents/watt for CEC approved panels.... I just bought 10kw from up there for $5000
At 50c/watt, there is no future in a 1kw windmill compared to 1kw of solar..
The mill will generate probably 10% of sticker over time.... so it is really at best a 2.4kwh/day device.... and thats being very generous.... so if it costs say $500 to fix, then it would be wiser to buy 1kw of solar for the same money... and get over 4-5kwh/day average in Brisbane solar condition.....
Unless the repairs are cheap as.... put the money into solar, the returns are vastly superior, and maintenance nil..... and I like windmills.... but I don't like the maintenance.... so my two 4meter windmills are no longer up, but I still have my water pumper flying... but don't use it to pump water anymore... solar is much better at doing that too.
Put another way... this summer, your present 600w and another 1000w combined with your battery, will run your 800w airconditioner through a fair part of the day .... the windmill.... not even remotely likely.
.............ozutles
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yes im with you there but i did buy it cheap off a guy on ebay i got it $200 i won it the guy payed over $1300 for it he said ever got to use it as he lived on a boat and most of the time you try to get out of the wind he said it was to big for he boat so i got it off him so i come home got my wires stays and cables and then i got a sun grid tie 1000g with dump load on it i had it fine for 8mths then a big storm come one day blow up the grid tie so cost me $100 to send it back to china come back not working still wasn't till i pulled the dump load off that it work again. to me they didn't fix the relay that switched the to dump load they most not have fix that so take it off and work again for 2 more mths with no dump load small storm killed it again so i stop using it so the grid tie cost me $500 them $100 more to send back so lost $600 on the grid tie i still have it.
i got a 1000w gid tie just for solar and i put 600w on it and it last 2 hrs and died so i ever buy them plug and plug grid ties again. so the wind generator was cheap to put up $300 all put it up was just what to do with the power so i put it on my batteries just to charge up it was real good as i don't get sun at night just wind and that helped keep batteries volts up at night i'm not rich guy i try to do on the cheap all the time on a pension to get off the power bills
I have kids and they love the computers my son gaming rig big video cards its like a heater in winter lol. he room nice heated room and i freeze my ass off in next room i still have $350 power bills to love to get to the end but its going to take along time on my budget .
so long as i can get my blade fixed one blade bent it the tree it went into and a new pole $50 for my wind generator be back up at running it not alot of power but it helps its lost money if its not working yes
o best i seen come out of it was 589 watts in good winds
all my friends called me windy Sean but no wind gen down i lost the name think i need to add baked beans to my diet lol
not easy being green .....Sean
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i been looking on the back shed and trying to find the blades but i think that the people selling them went out of business so had to find them i try heat it up and bend it back see how it goes the blades on the back shed site there a guy on there got blades not same as my blades so i keep it down for know i going to get 4 cheap 250w solar panels off a friend $300 for 4 not to bad they 2nds off gumtree they have bad cells on them but still working i try get them in 2 to 3 weeks ...
i rent home here so have to put them in yard cant use roof i do have a tracker but its got my 3x 200w 12v panels on it there on a trailer in my yard that what i'm using to get my power for the lights led 12 in home and i have 12v led hdtv to 115l12v fridge for family of 6 here trying my best i get there one day its just the setbacks i get try me what do you do keep trying.....
not easy being green .....Sean
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I got help from a good guy ( David) in the uk, he had a you tube video showing the new LF power jack inverters i got to talking with him and he got help for me in getting the repair parts so i can get my inverter working again so yes my power jack is alive again thanks to david and justin talking with the sellers so i can get my repair parts...
i see there is a new part on my control board i maybe be a fix on it not sure so know i got it working again and i get my mate justin to look over the old parts and see if he can fix it still never know may work again
next i have to justin to look over it to do the mods to the unit to cut down on the stand by power and look at better cooling for it.
one more thing i need to see why i cant use it when my batteries are on charge i found this time i have my solar controller set on 14.4v i found the inverter over volts alram going off know and it turns off but if i put the volts set down to about 13.6v then its fine and it stays on not sure why its doing this as in the book for the inverter it says the high volt is 15v is there away to turn the volts up so it don't turn off as i like my battery bank set on 14.4v as i get better charge in my batteries that way
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I got help from a good guy ( David) in the uk, he had a you tube video showing the new LF power jack inverters i got to talking with him and he got help for me in getting the repair parts so i can get my inverter working again so yes my power jack is alive again thanks to david and justin talking with the sellers so i can get my repair parts...
Hi! Thanks for mentioning this - and great to hear of success. That's me . . . and I put him in touch with Cher.
On this thread, I had issues with the early LF inverters which decided to blow their FETs but subsequently the boards were changed and the 2nd generation power boards have given me very reliable service.
The reliable power boards have two rows of resistors in front of the FETs and the old version which tended to blow their FETs randomly only had one row.
Best wishes
OTW
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Sorry Sean, I didn't see this....overvoltage shut down.
It has been done a few times before, and maybe you have seen that, but the mot reliable way has been a 5v6 zener across resistor ( 10M ) R14. The cathode towards the computer chip... it won't happen again, but you may have problems with over charging with using the charger... which I don't use so don't know for sure.
..............oztules
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sorry mate for the long time to reply i got some help to put a (10m) on the R14 but when i went to put it on the new boards that come there was some small board hot glued over the top of where the R14 was so i ask the seller what to do and they said to add a (1m) to the under side of the board not to take the glued board off just to do that so i did it and WIN no more problems with it over voltage shutdown it runs fine with my solar on it and missus is happy it just works she washing machine runs good don't cut out anymore
it been working the washing and i do use my power tools on it and it works fine thanks to yourself and guy in the UK David thats the name(off the wall) on this site
I don't work it hard i haven't even done the anything to the standby power loss as its off most of the time only turn it on as i need it
i hate to see it die on me again but if it does it ok, as there help out there to get it fix again. but if it does my home be fine as most of the home is 12v gear know the 220L fridge and freezer 12v/24v and a 115L 12v and X2 50L 12v fridges one in the boat and a beer fridge LOL and the led lights in the home 12v the 24"hdtv 12v x2 and the fish tanks are 12v air pumps and the grey water tank 12v ozone generator and water pumps i almost have a full DC power home next be hot water tanks DC element to just put solar on that getting there but good to have my inverter for the last 240v gear in the home.
next thing i be trying with my solar setup is one of this
http://www.ebay.com.au/itm/2400w-smart-solar-controller-DC12V-24V-MPPT-100AMP-solar-panel-3-5-LCD-display-/251932296381?hash=item3aa855c4bd
i like to try it out see if it works fine as i don't see anyone have blow up yet on your site but i see you guys starting to talk about them the blue one with no screen on it but i like to try the one with the screen on it see how it goes i do have 16x 190w panels $50 each with a 5kw grid tie$300 on the home but i like to take the grid tie off and go to more off grid setup so i have panels there to use on it and some can go to the solar hot water use see how i go .
thanks again for your help mate and the time to help all of us out ....you one of the guys to help save as all ,planet needs more guys like you
go green Sean.
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im new here...i have a blown power jack 15k ...it blew when i turned of mains to inverter to go ups.....
question is what are the four driver transisters exactly (two are ny....two are my )....these are i think smd body types but what values are they.optos easy and fets easy
buzzz
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drivers here
click on picture for bigger.
[attachimg=1]
...............oztules
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just reporting in that my 8000w lf inverter has blown up again.
Not sure if i buy the pcb board or controller board as i think it the transformer that is damaged i got up today to smell that bad smell of some thing that was on fire only to find a bad squealing sound coming from the power jack inverter and run down to see what was going on i had a 240v timer pluged into it for my pool it not a big pool just a small ring pool pump don't even go over 100w.
there was smoke and a fire going off in the timer but this is the thing it was not even switched on the timer was to kick on at 9:00 and this was 5:00am when i here the poping sound and the smell of smoke i unpluged the timer out and here the sound still there on the screen said that there still voltage there but only about 204v not 240 like it was and there not a thing pluged into it and it says was using 134watts.
So i turned it off till i work out what happen to it i think i buy a newer kind of inverter maybe i have better luck with i not had the best of luck with my power jack inverter . maybe i get to trying to work out if it can be fixed as a back up down the track...
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Looks like it was not your inverter that caused the problem. With some $25.00 of ebay 4110 fets, some 47 ohm resistors a soldering iron and wick, a little attention to detail and you can have it running like new in an afternoon. (4 driver transistors as well). Its not as hard as it seems.
Have fun with it!
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Likely you need some better filtering on the output of inverter. I think a protective MOV in the timer likely was being killed over time. As this is a capacitor voltage dropper power supply, those spikes could have done in the current limiting resistor in series with the capacitor if there was no MOV.
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hi guys its been some time with my inverter setting there its time to have a go at fixing it got a mate going to help me out he like to know if I can use this mosfet http://www.ebay.com.au/itm/10Pcs-Ru190n08q-Ru190n08-Mosfet-N-Channel-Advanced-Power-New-Ic-D-/282467392416?hash=item41c45e5ba0:g:LfIAAOSwA3dYHdNv off ebay mine is a 12v 240v LF 8000w power jack tried to get some one ones off my 1st inverter parts from when they blow but there not the same if any one can help me out with the 12v inverter I know lots of you guys run the 48v inverter so not sure if anyone know whats best to use on the 12v inverter? thanks again
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Hi Sean :) Yes, that looks like a good replacement. Im not sure it offers an advantage over irfb4110 though. Its very close to 4110 spec but seems more pricey. Then again quality and location can be factors too, You can spend $7.00 usd each on 4110 for genuine IR parts or 50¢ ea on ebay. Must use complete set of one type though.
To compare devices look at::
Id (continuous drain current and pulsed drain current.) Same or greater than original.
Vdss (voltage ability) same or greater than original
Qg (gate charge) Less than or equal to original
Package style, ex, to220, to247. same as original.
Internal circuit, same as original
Sorry for late post, info is probably not necessary at this point.
Just in case repairing drivers is too much of a headache, you can buy the driver board for $20 usd free shipping now. depending on which cntrl board you have it may be a simple swap an ready to go.
Good luck with that!
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Not that things can't get into splitting hairs when crossing a suitable substitute part when combing datasheets already lol... but I'd like to add "avalanche rated" to lighthunter's cheat sheet list... It's ok for it to show up in the substitute and not be in the original, but sometimes can "bite you in the heatsink" the other way around. (Ok that was bad I apologize lol)
This is a complex attribute of a particular device in terms of what is going on under the hood, but in a nutshell, it represents a device's ability to "stay in control" when Vds exceeds breakdown and how it handles the energy internally.
This is relevant to any switching design because the key offender is inductance, and while the characteristics of the nearby components can be compensated for (this is what "snubbers" do), there is a practical limit for what can be accounted for when external loads and their wiring get involved.
I see in this case that both IRF4110 and RU190N08 are indeed avalanche rated, so you're good there, but felt it was worth mentioning as one of the more important considerations in general.
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Thanks Steve! i wasnt aware of the avalanche rating. Learned something new :)
Why dont we / or manufacturers put fuses on each FET (source) terminal , wouldnt this make repairs much more delightful for fellows or am i missing something? Fuse wire comes to mind.
Since i havent seen this in practice, im wondering if there is a pitfall in idea.
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Fuses are resistors with much higher resistance than the FET on. Source would be the worst place to place a fuse as any fuse failure would destroy the FET. Commonly a failed FET will also short G-S. If series gate resistors are used, you just look for the FET with the lowest gate ohmage to find the bad FET.
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Also, fuses take A-G-E-S to blow, compared to the time it takes a FET to self-destroy.
Fuses may reduce the carnage, but they certainly won't save the FET in most instances.
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The best thing to do ( I do anyway) is to protect the input with say 120amps of breaker... standard 240v ones will do. ( yes it is DC and it is high current I know that too) The 240v ones are typically $4.00 on ebay. They are not all the same, some weld shut on startup, most perform perfectly well. I use noark ones, they seem to run fine on <60vdc... DO NOT USE ON >60v DC though. I use 2 x 68amp ones on my inverters and battery strings for that matter.
EDIT: Further to the above. Clockman had a discussion with breaker manufacturers in Europe. They agreed that <60v, the 240vac ones are fine to use, but derate them 20%... thats it.
A big problem is the start current ( to charge the caps from cold at first turn on) This is in the order of over 400 amps, and is why ANY breaker will have a good excuse to weld up on start up splat. For some reason, most of the 240v ones seem to handle this ok, the noark ones from ebay do it with ease, and Ihave yet to see any untoward effects. Some of the other ones I have used... not so good. If you just splat the cable to the input bolts, you will so substantial damage to the lug or bolt threads... it is a big big surge..... especially on the 6 cap boards.
It is best to have a resistive charge up system, but my particular design will hang if the start up voltage rises too slowly, and requires a reset switch in the design. I think the PJ suffers this slow cap charging ok. Even a push button with 40 ohms in series to charge the caps will solve it all.
End Edit.
This protection may/may not stop fet destruction ( generally not)... but it will protect your circuit boards.
I do/did a lot of experimenting on these PJ and my own designs, and I don't care if the fets go bang, but I hate the burnt resistors, burnt totem trannies, and subsequent board damage. It is stupid and unnecessary.
So input fuses will stop the cascading noises you normally hear on failure. It is just breaker goes, and the drivers and the rest of it survives, and you generally only need to replace the fets.... and they won;t have blown the pads away either.
.......oztules...... expert destroyer of fets and other tender electronic components.
Like this
[attach=1]
[attach=2]
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Some great information guys!! :) Makes sense, i knew there must be a reason not to fuse a fet since I never see it in industrial design. I still think I could pull it off by using some hall effect latches but it may require a re-layout of main FET board. I wouldnt even concern about it except mine did blow up a month or so ago and there wasnt a reason for it to have happend. As I went through the possibillities it did happen at a time when house loads could have been fairly high 3kw+ and then a hair dryer and well pump may have started on top of that. The surge might have required current limiting which I admit there is a problem.
When i changed this inverter from single phase to split phase it left one of the two without current limiting. Since the PJ limiting ct uses a physical wire connection rather than just magnetic, i cant add the two together by running two wires thru hole in opposite directions like i did for the face display meter. I may have to remove the original ct and change it to an inductive toroidal type. Anyone know what ratio ct i need to do this?
Very nice looking inverter in photo!!
BTW, i am using a 100A marine breaker on the 48 DC side, it never opened. So i will try the two 240 breakers, maybe they are quicker and of magnetic trip style although I may try to go with two 50A ones.
Again! Thanks for advice!!!
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"Anyone know what ratio ct i need to do this?"...... no but nearly anything will do. If you look at the circuit coming away from the original CT, it goes to a obviously added on resistor after the initial smd assembly. By changing that value, you tune the new torroid CT ( plenty of 2000turn ones on ebay for peanuts).
If you put the torroid in series with the original CT (place the ac through the middle I mean) at some output, and read the ac rms output of the 2000t torroid... and the main CT......compare notes, and go from there.
In fact I use the 2000t ones in my 8010 inverters ( in pic). Just need to shunt it to give you the range your interested in. I generally cut out at 14kw ( about 60 amps@230v )
........oztules
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If you put the torroid in series with the original CT (place the ac through the middle I mean) at some output, and read the ac rms output of the 2000t torroid... and the main CT......compare notes, and go from there.
Just a heads-up warning for the uninitiated.
CTs are not well understood by a great many people. They're a *CURRENT* transformer with a fixed ratio.
If you pass current through the primary of a CT and DON'T LOAD THE OUTPUT, you can get DANGEROUSLY high voltages.
Oztules suggestion is perfectly fine, but please don't just think you can stick a meter across the toroid output "safely".
Put some load or "burden" resistor across it BEFORE you power it up.
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Yes the typical CT runs into a very low impedance, and the open circuit equation looks very scary
Vs=Vp(Ns/Np) Vs= secondary volts, Vp=primary volts and Ns=turns of secondary, and Np== primary turns.
The info this comes from this site...... very informative, and nice pics.
http://www.electronics-tutorials.ws/transformer/current-transformer.html
They do the calcs as Vs=240(2000/1)=480000 volts.
Their particular example was on a 480v circuit, with 160 turns:1... they got 76kv... wow..
In the real world though, the 2000:1 torroid with 2500watts going through the hole ( 240v@10 amps or so), produces only 35v open circuit... which is a little bit less than the 480kv their equations predict.... yes I went outside and tested it again to be sure.
I suspect there are differences I can't see, their diagrams are specific, but it don't add up.
Anyway, at 6kw you would feel a tingle, so stay under 5kw if you want to be pretty safe..
There are a lot of warnings regarding the average CT open circuit, so there is something in it for sure... I just haven't witnessed it first hand... all the testing I have done in this sphere is pretty woosy stuff.
So keep an eye out, where there's smoke there is fire, and Ross and other folks know lots more than me with this stuff .... but I haven't seen it first hand.... at all.
..........oztules
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In the real world though, the 2000:1 torroid with 2500watts going through the hole ( 240v@10 amps or so), produces only 35v open circuit... which is a little bit less than the 480kv their equations predict.... yes I went outside and tested it again to be sure.
I suspect there are differences I can't see, their diagrams are specific, but it don't add up.
Your use of a 2K turn xfmr works in your favor here. A lot! And this is one of the things I hinted at - CTs are quite counter-intuitive. I don't mean to hijack the thread...
Most of us tend to think that a transformer with "lots of turns" is going to make "scary voltages" and that "less turns is more safe". This is where the CT can bite. If someone were to take a transformer with only 20 turns (instead of the 2000 you tested), they may well be forgiven for thinking that it would be 1% of the output you have.... but it doesn't work that way! The transformer is going to try to generate 1/20 of the current in the primary, not 1/2000 of the current. So with your 2000 turn transformer, and a 10A current in the primary, it's going to "try to" push 5mA. With a 100R burden/load resistor, that'll make a whole 500mV. Without a resistor, it should still "try" to make 5mA, but as you found, transformer core losses, considerably less.
With our 20 turn transformer, it's going to try to push 500mA through the secondary and the secondary voltage (unloaded) will potentially be SIGNIFICANTLY more.
Even a conventional "off-the-shelf" CT to drive a 5A meter is designed to drive 5A into a meter with a coil resistance of 0.2 ohms (5 watts). If the meter is open-circuit for some reason (like someone working on it) .... well, lets just say, its the sort of mistake you only make once!