Re: Hockey Puck Caps

["Tesla list" <tesla-at-xxxxxxxxxx>]

Original poster: "Ed Phillips" <evp-at-pacbell-dot-net> 

Tesla list wrote:
> 
> Original poster: Mddeming-at-aol-dot-com
> 
> Hi All!
>         Has anyone had experience with hockey-puck type rf capacitors? I
> looking at 4 of these rated .004uf -at- 40KV. My plan is to run them in parallel
> to get 0.016uf -at-40 kV. With my 15/60 trannie, 60 Hz resonance calculates at
> 0.0106uf and the conservative safety margin of VAC(rms)*sqrt(2)*1.5 ~32KV
> shows they should be all right from that standard. I can find nothing on the
> power-handling capabilities of these in my references and at $25 a pop, I
> don't want to pop too many! The "lumeniferous vortex" a.k.a. (4.5" coil) is
> already swallowing too much of my pension check. Any guidance will be
> appreciated.
> 
> Seeking the Lightning,
> 
> Matt Deming

	Assume these are ceramic HV filter capacitors, not intended for AC or
RF operation.  If so, they'll work - I use similar capacitors here, 
However:

1. They are quite lossy and will warm up pretty quickly - you'd better
determine how long you can run before they get warm to the touch.  Don't
run longer than that or you risk the chance of catastrophic failure
(puncture shorts).

2. As they warm up the capacitance will change, detuning the coil. 
Probably a tolerable effect if you don't run them long enough to
overheat.

Ed