racing sparks and overcoupling (was - Re: Primary coil configuration)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: dest <dest@xxxxxxxxxxxxx>


> Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>

> As you lower the coil it hits a peak point well before racing sparks
> start. Racing sparks start when the fundamental begins to split
> approx 5-10 degrees off the peak none-split value.

"degrees"? i.e. it have the same frequency but its phase angle is 5-10
degrees differ? then it`s just not splitting.
do you understand that tesla transformer can`t work at all without
frequency splitting?
"degrees off the peak none-split value" - or you just mess "degrees" with
"peak value", i.e. amplitude?

> If anyone is interested they can contact me directly

> There is just absolutely no reason to design a coil that will have
> racing sparks in the initial design.  This data has already been
> compiled and is available from me.

and why this data can`t be posted to the list or Terry`s collection of
documents, in order to anyone can validate/trash it - is this a dark
evil secret?

> Dr. Resonance


when discussing racing sparks, everybody on the list are talkin about
the frequency splitting caused by overcoupling, and the best explanation
that i have ever seen was the Bert Hickman`s one:

"From: Bert Hickman
Date: Mon, 14 Oct 1996 19:19:43 -0700

[...]
higher coupling increases "frequency splitting" during energy transfers.
Since the pre-breakout Q of the secondary is typically much higher than
the primary Q (with gap), the primary "driving" frequency will be higher
than the secondary's natural frequency while we're "pumping" it.

If Fcenter is the uncoupled natural frequency of the primary and
secondary/toroid circuits, then Fupper and Flower for k=0.6 can be
estimated:

  Fupper = Fcenter/(sqrt(1-k)) = 1.58*Fcenter  (the primary "driving"
frequency)

  Flower = Fcenter/(sqrt(1+k)) = 0.79*Fcenter

Note that Flower tends to be depressed in the primary circuit when
Qsecondary >> Qprimary per Terman)

This implies that, while being excited by the primary, the secondary
voltage "peak" in a 2-coil system will appear somewhere between 1/2 and
1/3 of the way down the coil!
[...]"

but this explanation is wrong - Fupper is the resonance
frequency of the secondary circuit when coupled with primary, so there
is absolutely no harm in driving secondary at that frequency.
nevertheless, the secondary doesn`t resonate at Fupper - the secondary
voltage is a high frequency oscillation (Fupper+Flower)/2 which is
amplitude modulated by another low frequency oscillation
(Fupper-Flower)/2.

(Fupper+Flower)/2=Fcenter*(1.58+0.79)/2=1.185*Fcenter < Fupper, so
even for Bert`s example of extreme (0.6) coupling real secondary
operating frequency would be lower than its coupled natural frequency.

racing sparks? how?