Re: H/D Aspect Ratio . . . How much does it matter ? ? ?

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

Original poster: "D.C. Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>


If you are building a med size coil and using, perhaps, a 20 x 5 topload
with a small cap on the primary, then you in fact can get away with a 3:1
ratio.

If you are using 26 AWG magnet wire, ie, a lot of turns, then you should
consider the 4.5:1 ratio to prevent excessive strikes to the strike guard
ratio.  A lot of turns with a very large toroid produces the greatest spark
output, however, the slightly taller aspect ratio is better because with
this setup you need the height to prevent excessive strikes.

We've used many ratios on hundreds of coils built over 37 years of coiling
and the 4.5:1 is still my favorite for med size coils with great spark
output.  Example, our standard NST 15 kV 120 mA coil produces 6 ft. sparks
and aspect ratio is 4.5 : 1.  Primary cap is .05 MFD.

Dr. Resonance



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, September 09, 2002 10:49 AM
Subject: H/D Aspect Ratio . . . How much does it matter ? ? ?


> Original poster: "Mccauley, Daniel H by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
>
>
>
> I'm currently designing my next secondary coil using 12" PVC pipe.
However
> I've heard quite a bit recently regarding
> what the best Aspect Ratio should be for this sized coil.  I hear some say
> 3:1 and then others are saying 4.5:1.
>
> My question is what are the physics behind these numbers or has it been
> found out experimentally.  Also, if I don't follow the rules, say build a
> 12" coil with a 3.7 or 4.0 H/D Aspect Ratio, would I expect my coil a
> significant drop in performance (say greater than 25%) than if i built
using
> a 3.0 or 4.5 Aspect ratio.
>
> Basically, does H/D Aspect Ratio *really" matter, or is it just one of
those
> things that if done properlyl increases performance only slightly.
>
> Thanks again.
>
> "Captain Corona"
>
>