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Re: 25 kV PT

Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>

Adam - I wouldn't do it.  Not, at least, before doing
some more research on the particular unit.  I recently
found a GE JVT-200 PT.  200:1, 3kVA, two-bushing.
It's positively enormous, as PTs go!  Beyond hope, I
actually got an original hardcopy manual with it when
I picked it up.  The manual specifically says *NOT* to
ground one HV terminal unless operating at
substantially reduced voltage.  I forget the derating
factor.  It wasn't something obvious like 1/sqrt(2),
though.  It was even worse!  I assume this is all
because both sides of the HV are not insulated to 24kV
(or better) from the core.

I'm poking around on the GE site right now trying to
find hardcopy of my manual (which is in storage
now--I'm moving).

I've many times seen people advocate grounding one HV
terminal on two-bushing pigs.  For pigs--or maybe just
most stuff 14.4kV and under--this seems to be
generally ok.  Some study of the nameplate is probably
to be recommended, though!  Except for my 200:1 PT,
all my other utility-type transformers are
single-bushing, which makes life easier in my oninion.

Aaron, N7OE

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>
> I have 2 25 kV PT's like these:
> http://geindustrial.com/products/specs/pt62125.pdf
> Has anyone ever grounded one leg of a PT before? I
> know lots of folks have done this with their pigs
> (myself included). I'd like to run them in series
> for
> 50 kV out, but would hate to kill them.
> thanks
> Adam
> The fish are biting.
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