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Re: More Tuning/Debugging



> Would any one else like to try this measurement? Over volt the
> 110V tap of your pig and plot the current with the HV open. jim

 >Yeah, I've seen it too. 
 >
 >I have a 7200V-240/120 25KVA single bushing pig. After I
 >rewired it (HV and LV sides under the oil) for 14,400, two
 >bushing operation the idle current went from barely noticeable  
 >to around 10-12 amps at 240-260 volts. RQ

> Was this the pig that you posted about rebushing 3 or 4 months
> ago? If so, I didn't realize that you had rewound the primary 
> also. jim

I did not rewind, just rewired. I moved the LV windings into 
parallel, and have been pouring 240 volts into the 120 volt
coils. On the HV side I removed the grounded terminal from the
core and wired it through the lid of the can for a second
terminal. The end effect being I got a cobbled 14,400 v two
bushing pig out of a 7200 v single bushing pig. However after
playing with the thing for several months trying to get my coils 
to fire smoothly over a range of variac and current limiter
settings I am not satisfied with the performance.

> Suggestion for upgrading a 7200V pig to 12+kV?

Get a second pig that matches the first and place the HV windings 
in series. If you have two single bushing pigs you ground the
cans, place the LV windings in parallel, and use the HV bushing 
on each can for 7200 volts, 14,400 volts across both. I have done
this with plate transformers and this method worked very well.
Richard Hull has done this on pigs and potential transformers and
also reports excellent results.

Richard Quick


... If all else fails... Throw another megavolt across it!
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