Author Topic: High voltage transformer question  (Read 740 times)

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Offline Greg65

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High voltage transformer question
« on: August 11, 2017, 11:44:30 pm »
Dear forum,

I have been given a battery powered 6v-12v electric fence machine to repair that keeps cows and sheep from escaping the field. It can output up to about 5 or 6Kv that connects to a long wire that keeps them from escaping or running out on the road.

I have done my tests on the circuit board and the output transformer is blown on the primary side winding. The secondary side of the transformer connects directly to the electric fence wire.

I have removed the transformer and checked the primary side voltage on the circuit board which reads about about  6 or 7 volts pulsating on and off so that verifies to me that the control circuit and everything else is ok.

The problem is I don't know what type of transformer this is, obviously this a step up from about 6 or 7v to about 5 or 6Kv or so, is this a flyback boost type or a custom made one, I'm not sure!

Its a small pcb mount one with no markings at all on it,  here are a few photos;

Can you tell me what type of transformer this is and where would I get one as I have searched with no results? It doesn't need to be the exact dimensions,

Any alternatives would be greatly appreciated?


« Last Edit: August 11, 2017, 11:48:39 pm by Greg65 »

Offline Benta

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Re: High voltage transformer question
« Reply #1 on: August 12, 2017, 12:26:23 am »
Electric fences for livestock work like ignition coils, so yes, it's a flyback.
Where to get exactly that on is anybody's guess...
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Offline floobydust

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Re: High voltage transformer question
« Reply #2 on: August 12, 2017, 05:54:46 am »
Those both look like custom transformers, and the usual capacitive-discharge design.
The smaller transformer makes several hundred volts charging yellow capacitors and TO-220 SCR dumps this into the larger HV transformer. SCR usually fails short.

The transformer going open occurs usually at the wire bobbin attachment points. I'd take a good look there.
Pics are a bit blurry. Otherwise you'll have to get the magnetics from the manufacturer.
Got no hits for "TCI".

Offline Zero999

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Re: High voltage transformer question
« Reply #3 on: August 12, 2017, 07:36:56 am »
As mentioned above, it's most likely a capacitive discharge circuit. It will be very similar to a stun gun circuit.

If the break isn't at the start of the primary, you might sill be able to re-wind it. The primary is usually on the top and secondary in the middle, which makes things easier.
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