Re: Capabilities of Small Thin Wire Secondaries (fwd)

---------- Forwarded message ----------
Date: Tue, 28 Jul 1998 21:51:11 -0700
From: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Capabilities of Small Thin Wire Secondaries (fwd)

John Freau wrote:

> Initial specs:   Pri, # 12 stranded pvc ins. wire close wound flat
> pancake, 3.5" inside dia.  tapped at 18 to 21 turns as needed, about
> 87uH.  Sec, 3" by 9" styrene form tight wound with 1200 turns # 34
> isomid enamel wire, 30mH.  Toroids, 1.5" by 4.5" placed on top of
> sec, with a 3" by 12.5" alum. dryer duct toroid on top of the small
> toroid, with metal spacer in between.  Static gap is (24) 1/2" by 2"
> copper pipes glued to a board, spaced 8.5 mils similar to Terry F's
> design.  Powered by one or two 9kV 30ma NST's.  Cap is .007uF
> polypropylene.  No safety gaps, chokes, resistors, etc.

Very interesting post. This specification is very close to a coil that
I am building (rather slowly...).

About those "racing sparks", what would be their cause? Where they
appear? By your tests this phenomenon is associated with high couplings
and some problem in the primary gap.
May the problem be caused by excitation of higher-order resonance modes
in the secondary coil? The fast envelopes of the secondary waveforms,
or those peaks at the primary gap transitions may reasonably excite 
transients at these other resonance modes, causing intense electric 
fields along the secondary.

Antonio Carlos M. de Queiroz