Re: "Astro-Coil P1"

Tesla List wrote:
> >From richard.quick-at-slug-dot-orgSun Aug 18 12:23:37 1996
> Date: Sat, 17 Aug 1996 07:24:00 GMT
> From: Richard Quick <richard.quick-at-slug-dot-org>
> To: tesla-at-poodle.pupman-dot-com
> Subject: Re: "Astro-Coil P1"
> Quoting coco-at-astroman-dot-com:
> > I also picked up the following capacitors:
> > 2mfd 10kv  (two of these)
> > 1.6mfd 36Kv (one of these)
> Quoting R. Hull:
>  > Most of these PF correction caps are either paper or
>  > paper/plastic dielectric and can be used for pulse work,
>  > though not ideal for the purpose.  The caps you have are far
>  > too high a value for anykind of Tesla work, as is.  RHull
> Back to coco-at-astroman-dot-com:
> > With those caps. I mentioned... (the 2mfd. 10kv), you mentioned
> > that modification would be ness. for any Tesla Coil usage.
> > would this modification be more than just series-ing enough of
> > these to get the value down to a reasonable level (and thus
> > increasing the voltage rating), or is there design differances
> > with these caps. that require modification (thus not really
> > being worth it for that type of usage) (Granted..it > would
> > take quite a few of these)
> The cans have to be opened and the contents examined. HV
> capacitors are generally built from several sub-units that are
> wired together in the can. To obtain a very high value (i.e. the
> 2 MFD) many sub-units are wired in parallel to build up the
> value.
> For Tesla coils a .2 MFD cap is getting pretty hefty and a 2 MFD
> is not at all practical; also the voltage rating must be higher
> than 10KVAC in order for the cap to survive in most coil systems.
> The solution is to rewire the sub-units in series rather than
> parallel in order to reduce the value and increase the voltage
> rating. The dielectric losses in many PFC caps (Power Factor
> Correction caps) become large when the caps are used in Tesla
> service, so unless the dielectric is all plastic expect to keep
> your run times short.
> Richard Quick
> ... If all else fails... Throw another megavolt across it!
> ___ Blue Wave/QWK v2.12

    Since this will be my first coil. How long can I expect to run a 
coil before it has to be shut down, and cooled off?