Re: 25 kV PT

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi DC,

Assuming the PT's in question can have one of their HV bushings 
grounded, then I see no problem.  Since they are identical, their 
secondaries are most certainly wound the same direction.  If one were 
to reverse the LV connection to one of the PTs then when one PT HV 
bushing goes positive, the other will go negative and you end up with 
50KV between the two ungrounded HV bushings of the two PT's. The 
maximum voltage anywhere is 25KV with respect to ground so neither PT 
sees the 50KV.

I think the real question is can the PT have one of its HV bushings 
grounded and if so, which one.

Gerry R.


> Original poster: "resonance" <resonance@xxxxxxxxxxxx>
>
> If he uses two similar xmfrs with both coils wound in the same 
> direction both xmfrs will hit a peak of 25 kV at the same time while 
> they are at 0 potential on the opposite 1/2 cycle swing.  With AC he 
> will only see 25 kV to ground and will not see the 50 kV peak to 
> peak he is trying to obtain.
>
> Maybe I missed something here but I don't think this will work as he 
> is planning to use them to develop 50 kV peak to peak between the outputs.
>
> If he had two coils wound in opposite directions and tried to 
> operate them in epoxy there is a very high proabability they would 
> fail.  Operation above 25 kV produces high corona content and all 
> xmfrs that I know use oil instead of epoxy for these high voltages.