Re: Capacitor help

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Bart,

I don't have any direct SRSG experience yet, but can make reference to
Richie Burnett's web page on SRSG theory of opertion.  I think the SRSG LTR
cap value is optimum for largest power processing for NST's.  Taking
advantage of both resonant rise and inductive kick with the proper phasing
of the rotary gap, a maximum Vcp (not exceeding the NST rating) can be
obtained at presentation.  Of course with a PDT, overvoltage is less of a
concern and synchronous application with higher than 120 BPS is a
consideration.

I did, however, perform some careful experiments using a multiple static gap
(set so the safety gap would occasionally fire) with a 4500/22 NST being fed
a constant 120 Vac and I varied Cp in small steps to characterize the spark
performance.   I started with a 2.2 * Cres and worked down to 1.2 * Cres and
I got my best performance at 1.57 * Cres which corresponds toTerry Fritz's
calculation for 120 BPS.

Gerry R
Ft Collins, CO

 > Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
 >
 > Hi Mark, All,
 >
 > I just noticed the "reason" you are looking for an LTR cap was to achieve
 > possibly longer sparks. I almost always run a PDT which forces me into an
 > STR cap. From my understanding, LTR values do not give longer sparks or
 > anything of that nature, but are used to reduce the stress on the NST in
 > SRSG situations. The static gap apparently is also to benefit in this same
 > respect. The tradeoff is capacitance for voltage.
 >
 > I sometimes get the impression coilers think using LTR gives greater spark
 > lengths, but again, this is not my understanding from past posts on this
 > subject.
 >
 > Comments, anyone?
 >
 > Take care,
 > Bart