Re: toroid dimensions

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

Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>

Jeff,
     there do not seem to be many "optimums" in TC building, personal
experimentation seems to be the order of the day, especially in the area
of toroid size. Generally bigger is better, but I've tried 2x8" and 3x12"
on my mini (3.5x12") coil and in this case I don't get longer sparks from
the larger toroid - even though I increase my primary cap size to keep
everything in tune and that should give me more energy per spark, at least
in theory!

The absolute best way to determine resonant frequency of the TC secondary
and its toroid is with Terry Fritz's  E-tesla-6 program. I've used it and
had no problems (I'm a programmer so compiling and running it were simple,
but I think you can down load a ready-to-run PC executable too).

http://hot-streamer-dot-com/TeslaCoils/Programs/Programs.htm

My suggestion is to build two, maybe more, toroids and try them out. At
least for me experimentation is a large part of the fun. Now if I could
just find the time to have some more fun...

-Peter Lawrence.


>
>Hi all,
>Is there an optimum physical size for the topload terminal?  I bought some
>4" dryer duct planning on making a 22" total outer diameter toroid for my 6"
>x 24" secondary (27.5mH).  Using a 15/60 NST, a 10.5 turn .4" spaced 3/8"
>copper tubing primary (56.9uH).  The topload capacity should be 23pF
>(WinTesla) giving me 164.6 kHz res freq.  I've read descriptions of other
>coils similar to mine with and I'm concerned my toroid may be too small.  Is
>there a way to measure its capacitance?  I have a signal generator and scope
>at home.  I've read about using a "grid dipping" method to measure primary
>and secondary resonant frequencies for tuning.  Maybe you could measure the
>secondary without toroid and then with to deduce topload cap.  Anyone tried
>this?
>
>Jeff Johnson
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