Re: Designing BIG Secondary Coil

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

Dave,

If the coil is too short for a given bang size, sparks may run 
along the full length of the secondary, or break it down at
various places as you mention.  This is much less likely to
occur at a high breakrate, since a smaller bang size can
be used for a given sparklength.   Can you even measure
the sparklengths accurately in your basement?  Certainly
sparks up to 3X or 4X the length of the resonator or longer can
be produced without a problem, especially at higher breakrates.

Yeah, I'm not able to fire coils outdoors here either, which is
a bummer.

I've always had the idea that the secondary diameter should
be related to the spark length and toroid size.  You want the
toroid to dominate the secondary diameter by 3X or 4X for
best results I think.  For all I know, maybe it's not really that
important though.  I haven't really done a whole lot of tests
of that.  

Then there's the issue of how to get the longest sparks from
a physically small coil, which is related to the above.

John


>
> John,
> I assume you are referring to inter-turn insulation breakdown. As I was
> telling the good Dr. R, I was thinking about a ~12" x 24", wound with
> something like #20 wire. The hope is fitting max perf in my vertically
> challenged basement (7'); though what is the point? This new 4" x 24" sec is
> already overwhelming the area. An exercise in efficiency, I suppose.
>
> I envy the boys that are able to fire outside, which is unthinkable in my
> classically suburbian environs.
> Dave
>