Re: Power factor correction capacitors for MOTs

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

Original poster: "Ed Phillips" <evp-at-pacbell-dot-net> 

I have a question which I've posed before, without what I considered as
a satisfactory answer.  Since the secondary of the HV transformer
already has a capacitor across it, perhaps of greater than resonant
value, what function does the PFC capacitor on the primary perform?
What's it correcting for?  More importantly, how can you really select a
value without taking the secondary load into account?  I can see where a
big capacitor across the line will reduce the glitches in line current
caused by the firing of the gap, but other than that the usefulness is
not obvious.

	A few years back I experimented with PFC capacitors and a small coil I
have here.  I could reduce the no load current of the NST alone (no
secondary connection) from a couple of amps down to near zero, but
capacitors didn't have much affect on line current when the coil circuit
was connected and firing.  Under the conditions I was running the line
current was about 6 amps with or without a capacitor.  I could increase
the current above this by using a very large capacitor but why do that?
I should have taken notes but........

Ed