How low can a spark gap go?

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Original poster: G Hunter <dogbrain_39560@xxxxxxxxx>

Thanks for all the feedback on spark gap behavior. The
level of expertise on this list regarding electricity,
electronics, physics, mechanics, engineering, computer
modeling, problem-solving, etc., etc. is simply
outstanding.

I've got a copy of Dan McCauly's DRSSTC book, and I've
been studying his IGBT-based coils. His designs are
elegant. However, I am dismayed by the high parts
count and the overall complexity. I don't think I'm
yet ready to tackle such a project. I appreciate
McCauly's pioneering work, but I'm more settler than
pioneer. In a few more years, big IGBT SSTCs may well
be the norm for the hobby.  Until then, I'm going to
continue using stone knives & bear skins.

Which brings me at last to the point of my post. Dan's
DRSST is using really modest tank cap charging
voltage! Only 340VDC (doubled 120VAC) or perhaps
680VDC if the doubler is followed by resonant
charging. Those are trifling potentials for someone
brought up on NST and MOT-based coils! I'm wondering,
can something similar be implemented using a triggered
spark gap? How low can the firing voltage go on one of
those? Think along the lines of doubled 240VAC
followed by a charging reactor for 1.3KVDC. Using a
fat tank cap and an air-blast quenched TSG, could such
a scheme achieve reasonable performance? I know the
gap will be lossy, but a bigger tank cap (200nf or
therabouts?) could compensate. The secondary would
have to be wound for rather low frequency in order to
have a reasonable number of primary turns, but that's
no big deal. Anyone ever tried a low voltage SGTC
before? Is this a hopeless notion?

Cheers,

Greg




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