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Re: Capacitors
Tesla List wrote:
>
> >From jim.fosse-at-bdt-dot-comSun Sep 15 21:38:46 1996
> Date: Sun, 15 Sep 1996 21:29:54 GMT
> From: Jim Fosse <jim.fosse-at-bdt-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Capacitors
>
> >Date: Mon, 09 Sep 1996 14:40:11 -0700
> >From: Richard Hull <hullr-at-whitlock-dot-com>
> >To: tesla-at-pupman-dot-com
> >Subject: Re: Capacitors
> >
> [snip]
> >Does your cap glow with corona when it is run? Put two or three
> >in series until no corona exists.
> >
> Richard,
>
> In this old post to Julian, you mentioned a corona glow in a
> polyethylene cap. Is this under oil? That is: can you see a corona in
> a poly cap under transformer oil when you run it close to it's maximum
> voltage level?
>
> I'm asking because I've blow my 4 home rolled caps. Each was evacuated
> to <10^-2 torr, filled with oil and then pumped down again. I am
> guessing that I am just over voltageing my caps but will watch for
> corona if it is observable.
>
> jim
Jim,
All items corona at some given voltage in oil. This point is much higher
than in air, but still exists. If you have corona you have ion
production, and therefore, conductive paths. I find that polyethylene
coronas around 10KV or even less in some oils. I would recommend a
minimum of two poly caps in series if you use 12KVAC or more in your tank
circuit.
Richard Hull, TCBOR