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Re: Re: Reducing Self Resonance In Rolled Caps

On Sat, 19 Feb 2000 Tesla List  wrote:
> Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> 
> 
> Hi Malcom,
> 
> Original Poster: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz>
> >Hi Reinhard,
> >> Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>
> >> I hate to blow your dreams, but been there, done that => doesn´t
> >> work for long. Building a rolled poly cap (whether it be extended
> >> foil design or not) and getting it to run w/o oil WON`T work. Period.
> 
> >It can be made to work. I produced a design which increases the
> >creepage distance between plates to as good as infinity. The design
> >was published in Electronics World in 1995. However, air running
> >gives the caps a limited lifetime which can be quantified quite
> >accurately (I got about 40 minutes total runtime before the plastic
> >gave up in each cap I built).
> 
> Well, that is kind of what I meant. I tried your design and it turned
> out to be one of the better types. But I, too, had problems with
> the air (ionization, etc) and lifetimes of 40 minutes (my best time
> was around 65 minutes, using a slightly different config) are not
> quite what I would call reliable ;o)). Sometimes, I actually cooked
> out the plastizers in the PE, which in turn would turn yellow and
> harden. For a reliable cap one would need to go really low on
> the voltage per layer (and cap), making it unpractical (esp. if you
> are a high voltage coiler ;o)).
> 
> >I agree that MMCs are the way to go however.
> Yes, I think it is a true milestone in TC technology ;o))
> 
> Fantastic article BTW. I had the joy to read it in 1997. Terry
> has it on his website somewhere, I believe.
> 
> Coiler greets from Germany,
> Reinhard
> 

Hi Malcolm, Reinhard and the rest of you C^4's,

Ok, ok, I'am convinced. But it's difficult (for me) to ignore the
tremendous supply off plastic for free or very cheap. Could the extended
rolled cap design be improved by applying silicon to reduce creep arcing
over the plates?

Ruud de Graaf
Greetings from lovely and wet Holland.