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Re: Ballasting 1.5 kVA potential transformer
>Original Poster: Scott_L_Hanson-at-notes.seagate-dot-com
>
>There is a fair amount of data in the archives on ballasting pole pigs, but
>I have not seen anything specific to potential (metering) transformers. Are
>there any significant differences vs ballasting a pole pig?
>
>Does anyone have any first-hand experience & recommendations with primary
>current control on a 14,400/120/1.5 kVA transformer? Are there any
>specific references anyone is aware of in the archives, etc? Transformer
>will replace paralleled 15/60 NST's driving a 6.25" X 30", 21 ga secondary.
>
>Any input is appreciated.
>
>Scott Hanson
Hi Scott,
It's pretty much the same idea as limiting a pole pig, you are just using 120v
instead of 240v. I've ballasted PTs using microwave oven transformers, but
it was not ideal since the uWave transformers tended to get incredibly hot
after
a few minutes. Since you already have a couple of 15/60 neons, could actually
ballast your PT using the two of them. They are current limited after all,
and
each pulls around 900 watts. You'd short each neon's HV terminals, parallel
their 110v primaries, and wire one leg of the 110v supply to the PT in series
with the paralleled neons. That would limit your PT to around 1,800kVA
...which
is only a bit more than it is rated for. Another option would be to use
one of those
portable handheld 110v welders in series. That would give you variable
current
control which is always nice. You can also gap and rewind an old variac
core to act
as a limiting inductance, but I'll let someone else describe that since I
haven't tried
it myself .
Where did you find your PT by the way? I am looking for another myself.
Zap!
Charles Brush
http://www.foundrygroup-dot-com/cbrush/fun