HV transformer yay/nay

This forum is for specialized infomation important to the construction and safe operation of the high voltage electrical supplies and related circuitry needed for fusor operation.
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Thomas Sheeleigh
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HV transformer yay/nay

Post by Thomas Sheeleigh » Mon Mar 26, 2018 9:32 pm

Hi, i'm not sure if this is the place to do this but I was looking for a transformer and I found this http://r.ebay.com/h46fv0 . I was wondering if this looks sufficient. I only ask because there seems to be very little information online about it although I found the manufacturing company. The winding ratio is 2400/120 which seems a bit small. Does this transformer require some input voltage higher than I would be able to supply as a consumer? Thanks.

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Bob Reite
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Re: HV transformer yay/nay

Post by Bob Reite » Mon Mar 26, 2018 10:48 pm

That is also known as a "potential transformer" it's used to reduce a 2400 volt medium voltage circuit down to 120 volts so that it can be measured without having the real high voltage at the meter. The ratio between the input and output is very accurate. IMHO, not useful at all for fusor work.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

Thomas Sheeleigh
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Re: HV transformer yay/nay

Post by Thomas Sheeleigh » Mon Mar 26, 2018 11:46 pm

I see, thanks for the quick reply

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Richard Hull
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Re: HV transformer yay/nay

Post by Richard Hull » Tue Mar 27, 2018 5:05 am

As a result of my Tesla coiling days, we have a scrap yard that used to get in about 40 or 50 P.T.s each month, all through the 1990's. They were good pulls as Dominion power upgraded to total electronic metering around here, back then. All of ours were 70:1, 100:1, 120:1 & 140:1. A few rare, giant 170:1 or monster 300:1 units would be found at the yard, The bulk of them were 100:1 and 120:1. I bought about 20 of them and sold all but 4 which I retain. P.T.s are good for a solid 1.5kva and are readily pushed to 3kva+ for short Tesla coil runs. I have one 170:1 which, if doubled, would do good for Fusor work.

All P.T.s that we found of 170:1 or 300:1 ratios were oddly single ended. all 140:1 and smaller ratios were center ground, double ended like neon sign transformers. The 60 pound double endeds sold at the "yard" for $30.00 each. The 140:1 units were $40.00 The 170:1 units were about 200lbs and sold for $90.00 and the four 300:1 units were over 300 lbs and were $150.00. Our own Alex Tajnsek bought all of the 170:1 and 300:1 transformers to ever end up in the scrap yard. He had to have them. Most still adorn a corner in his lab.

Note: All the P.T.s, regardless of ratio, were potted in a hard rubber like compound! Gone are those glory days of cheap non-GFI, used neon transformers, honkin' P.T.s and iron core x-ray systems, all sold at scrap prices.

Most all P.T.s have more than sufficient power, but high enough ratios for fusor work are rare.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

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