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RE: caps an the resonant freq.

Fr. Tom:
Forgive this one for being a bit surprised.. While I most certainly
agree that wiring in series is a good thing, I am a little hesitant to
suggest that anyone plan on single thickness caps. After all, it is
both well known and documented that multi-layer caps are more robust
due to the fact that possible defects will not align.
Personally, in my poly caps, I used 5 sheets of 6 mil plastic as the
basic dielectric, and then wired 3 of the same capacitance in series.
So far,after about a year of use, no failures. I've used them
at 12KV/30ma, 12KV/60ma, and recently 14.4KV/200ma (approx). My only
problem is that they leak at the top seal (due to a screwup on my
part, don't try and make square o-rings )

Pictures of the caps in question can be seen at :
http://www.access1-dot-net/mycroft/baby.htm  [when I was using them on my 3.5"]

Michael Baumann
Coiler, Homebrewer, Nerd. mycroft-at-access1-dot-net


> -----Original Message-----
> From: Tesla List [mailto:tesla-at-pupman-dot-com]
> Sent: Friday, February 12, 1999 10:59 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: caps an the resonant freq.
>
>
> Original Poster: "Thomas McGahee" <tom_mcgahee-at-sigmais-dot-com>
>
>
> Kerry,
> Follow Ed's advice, but instead of building up the poly in
> multiple layers,
> make two or three single-thickness caps and wire them in series. This will
> make for a much more robust cap, and the extra aluminum foil is dirt
> cheap.
>
> The reason why such multiple series caps work out better is that each
> cap section only sees a fraction of the total voltage, and thus
> localized corona effects are GREATLY reduced. Corona is the great
> killer of caps. Most people who have used this technique would never
> go back to the old multi-layer cap designs. Try it.
>
> Fr. Tom McGahee
>
> > <<
> >  well I am reading the articals in the arcives about caps, and
> I read some
> >  people are using .06" poly, or it reads 6 mill poly, my
> question is, is it
> >  hundreths of an inch or thousands that i should look for I got
> 2 sheets of
> >  hdpe of .03" thickness and I just want to make sure that I am not
> wasting my
> >  time building the caps with the wrong thickness of plastic
> SNIP
> >
> >  kerry
> >   >>
> > Kerry,
> >
>
> > Two sheets of .030" thick ldpe or hdpe is what you want -
> depending on the
> > desired operating voltage of course.  In my opinion, two sheets
> of .030" is
> > good for about 9 kv ac maximum.  Three sheets are good for 12
> kv operation.
> > You first calculate the resonant frequency of the secondary using its
> > inductance, self capacitance and the added capacitance of the top load
> > (toroid).  Now you calculate the resonant frequency of a
> primary coil and
> cap
> > to match the secondary frequency.
> >
> > Ed Sonderman
> >
>
>
>