Re: capacitors

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

Original poster: "david baehr by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dfb25-at-hotmail-dot-com>


Keep your rolled poly caps IN OIL 

>From: "Tesla list" 
>To: tesla-at-pupman-dot-com 
>Subject: Re: capacitors 
>Date: Sun, 07 Oct 2001 14:49:01 -0600 
> 
>Original poster: "Malcolm Watts by way of Terry Fritz " 
> 
>Hi Greg, 
> My experience with banks of PP caps is that they perform as 
>well as any caps you could otherwise obtain. I used to roll extended 
>foil caps using polyethylene sheeting (same ballpark losses as PP) 
>and kitchen grade Al foil. On switching to the multi-PP caps, I got 
>sparks that were a little hotter and a little longer for the same 
>input power. The only significant difference between the two was a 
>lack of corona in the caps (the rolled caps were dry-fired). It is 
>imporant that you use plenty of strings in parallel to give high 
>discharge currents with low I^2R losses in the cap as a whole. 
> 
>Regards, 
>Malcolm 
> 
>On 6 Oct 2001, at 11:28, Tesla list wrote: 
> 
> > Original poster: "Mr Gregory Peters by way of Terry Fritz 
>" 
> > 
> > Hey everyone, 
> > 
> > As most of you know, I am in the process of building a large coil (up 
> > to 10 kVA). I am currently investigating capacitors. I have had it with 
> > constructing oil filled rolled or plate poly caps (I've made 6) - too 
> > messy, too many hours! I read with interest, some pages where people 
> > have used banks (up to a couple of hundred) of commercial polypropylene 
> > caps. I was wondering how well these work - are the sparks nice and 
> > hot, or thin and purple? I was also after some construction guidelines - 
> > most of these caps have thin leads, therefore requiring a complex 
> > series/parallel arrangement to handle the current. What resistor 
> > arrangement is used? How does the polypropylene stack up to LDPE as a 
> > dielectric? Are these huge banks alot less efficient then a simple 
> > staked plate cap? 
> > 
> > Cheers, 
> > Greg Peters 
> > Department of Earth Sciences, 
> > University of Queensland 
> > 
> > Phone: 0402 841 677 
> > 
> > 
> > 
> > 
> > 
> 
> 
> 
> 


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