Re: series pigs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>



Tesla list wrote:
> 
> Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<evp-at-pacbell-dot-net>
> 
> Tesla list wrote:
> >
> > Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <jimlux-at-earthlink-dot-net>
> >
> > No real problems... The insulation on a typical pole pig is rated for much
> > higher than the normal (10-15kV) primary voltage because of lightning and
> > switching transients  (80+ kV is typical) .
> >
> > If your pigs are the kind with one side of the primary (hv winding)
> > connected to the case, you'll have to run them with the cases connected
> > together.
> 
>         That last sentence sounds like total disaster to me!!!!!  Whole case
> hot?????
> 
> Ed

no... more like a center tapped NST.. Cases grounded, connected together,
the two hot leads coming out with 2*Vpig between them...

Pig terminal:HV winding:CASE --wire--GROUND--wire--CASE:HV winding:Pig Terminal


If you hooked them up

Pig terminal:HV winding:CASE --wire-- Pig Terminal:HV winding:CASE

at least one, if not both, cases would be hot.  This would probably work
(depending on insulation from LV winding to case), and has been used for
cascade type HV test supplies (although, often, there is an isolation
transformer from source to LV winding on the higher steps in the cascade,
just because of LV:case insulation problems)