RE: Variac and stationary gap TCs

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

Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com> 

An interesting question!  Yes, if your cap is mains-resonant, your NST/cap 
will achieve resonant rise sufficient to fire the gap at a very wide 
variac-range, not just near the top.  But even with a cap that is 2X LTR, a 
static gap will fire over a surprisingly wide variac range.  I would 
recommend the use of a variac regardless of cap LTR-ness and gap type.

Regards, Gary Lau
MA, USA


Original poster: Thomas <tom-at-pwrcom-dot-com.au>

I was wondering how useful a variac would be to control the power to a
stationary gap TC.

As the firing voltage is set by the gap distance, would a variac be any use
at all (other than for increasing the voltage, a la autotransformer style)?

My tank cap is resonant with the NST, so would the resonant rise let the gap
fire over a small range near the upper end of the variac setting?

Tom.