Re: Sparklength inquiry

To: tesla-at-pupman-dot-com
Subject: Re: Sparklength inquiry
From: Greg Leyh <lod-at-pacbell-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Sun, 27 Sep 1998 14:49:05 -0600
Approved: terryf-at-verinet-dot-com

> Original Poster: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>


> Now enters the question that has been the subject on this List for some
> time -- how to determine the optimum break rate.  It will vary with each
> system, however, one can optimize the break rate or pps for each system.
> Up till now everyone has been discussing the sec spark length, however, to
> determine optimum break for any system another important factor must be
> considered -- how many watt-sec of energy is lost in the primary spark gap.
[snip]
> The idea here is to carefully achieve a good balance between the break rate
> which at higher power levels does produce longer sparks and the total
> combined losses each individual spark gap represents.

IMO, the optimum break rate is the one that establishes 
the longest sparks through the ion cloud for a given 
primary power level, which is Ep X BPS.
Slower break rates don't fully realize the coils' capacity
for making sparks, and speeds faster than the ion lifetimes
only make the discharges grow bushier rather than longer.
So when I consider a coil, the design flow usually goes:

A) What size coil will provide the desired arc length?
B) What is the optimum break rate for the secondary structure?
C) How much output power will be needed to drive the secondary 
   structure (coil+toroid) to its fullest operating point?
D) What primary circuit (and sparkgap) can provide this power?

The break rate vs. gap losses trade off should only have to be 
considered if the gap design is fixed, and can not be upgraded 
to handle the full power requirements of the secondary.
-- 


-GL
www.lod-dot-org