Re: Overvolting pigs?

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

Original poster: "Paul Marshall" <klugmann-at-hotmail-dot-com> 

I have some experience with this. I had some 30kV pluse caps that I wanted 
to charge, but my pig was only rated for 14.4. I fed 440v to the primary 
with limited current, the result was about 28.8kV on the Hv side. It draws 
about 10 amps with no load on the secondary at all. It's not a good Idea, 
but it will work in a must do situation for short peroids of time.

PS: The 60 Cycle humm of the core was awsome.



Paul S. Marshall





>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Overvolting pigs?
>Date: Wed, 14 Jul 2004 07:35:09 -0600
>
>Original poster: "Sean Taylor" <sstaylor-at-uiuc.edu>
>
>It's not a question of how long would the pig withstand the overvoltage,
>but if you could even get it to that voltage.  I think I remember someone
>saying that they ran a pig to 300 v in and it started saturating (too high
>of a magnetic flux density in the core).  All that will happen if you put
>240 V into the 120 taps is you'll get excessive current draw and heating
>of the core.
>
>The same goes for running the RSG from the NST: it would saturate from the
>28.8 kV on the secondary.  NSTs are made fairly inexpensively, they aren't
>even designed to withstand the full rated voltage forever, as when they
>are loaded with a tube, the voltage is supposed to be around 1/2 of the OC
>output.  Another problem with the NST is the internal current limiting -
>the load of an RSG would certainly drop the voltage on the primary from
>120 rather quickly, and phase control would be a real problem, as the load
>changes, the phase changes.  I was thinking about doing a PLL type
>controller for a RSG using the primary cap's voltage as a reference
>waveform so that the RSG phase would stay sync'd with the primary voltage
>no matter what the input, though that's still a long ways off.
>
>Sean Taylor
>Urbana, IL
>
>On Tue, 13 Jul 2004 22:04:18 -0600, Tesla list <tesla-at-pupman-dot-com> wrote:
>
>>Original poster: FIFTYGUY-at-aol-dot-com Folks-
>>
>>      After recent posts on running small low voltage x-formers
>>backwards, and
>>trying to power a 480V pig with 240V:
>>      How much over the nominal voltage ratings will a typical pig
>>withstand?
>>I.e., if I put 240V into 120V taps how long will it put out twice the
>>high
>>voltage rating?
>>      Seems a lot of folks variac the 14.4kV units to about 18kV out - any
>>guesses how long it would withstand 28.8kV out?
>>      While we're at it:
>>      What, if anything, should be hooked up to the neutral tap of the LV
>>side
>>of the pig? Any theories as to balancing, filtering, etc., or is it
>>better
>>left unconnected? I feel the fewer house wires headed to HV land the
>>better.
>>      And speaking of running x-formers backwards and house wiring
>>isolation, I
>>was thinking of using a NST run backwards to provide 120VAC for the SRSG
>>from
>>the HV pig output to the primary circuit. So I suppose I should ask how
>>long
>>a 15kV NST will last with 28.8kV into the secondary...
>>
>>-Phil LaBudde
>
>
>
>

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