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Re: Maxwell Capacitors

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Justin,



Original poster: Just Justin <rocketfuel@xxxxxxxxxxxxx>
I picked up a Maxwell pulse cap rated thusly:
Voltage: 35kV
Cap. (Meas.): 30.7uF
E.S.L: ~0.02uH


I'm assuming that you meant that you "measured cap"
is 30.7 "nFd", not "uFd". 30 UFD would be more suited
for quarter shrinking than Tesla coiling.

I would like to use it with my first coil, which is
a full wave rectified 12kV NST (~17kV peak DC).
I'm not planning to use a charging reactor at this time.
I will pursue that avenue when I move up to MOTs (otherwise
I'd be looking a tank cap voltage of 35kV!).
I just thought I'd ask if anyone knows of any gotchas that
I should be aware of that could possibly raise the primary
circuit voltage above the 17kv DC coming out of the PSU?
I know with AC there is the issue of resonance in the primary
circuit that can raise primary voltage through the roof, but
since my PSU is DC, that seems like it should be less of an
issue.  On the other hand, there will be some ripple (or a lot,
if I can't find some cheap filter caps!) which I imagine could
end up resonating with the cap as well.  Am I correct in assuming
one would use 120Hz as the frequency in calculating the resonant
capacitance of the NST-Tank Cap system?  Does it even apply here?

Ok, HERE is where you COULD use a 30 uFD cap ;^) Filtering
out ripple requires some relatively huge capacitance. I'd have to agree
with Dr. Resonance on the "don't use DC" though. DC would be harder to quench at the SG and AC is just generally a lot less complicated to
use than AC, not to mention the very lethal energy levels that would be
stored in the filter cap(s). You would probably have to use several seriesed MOT secondaries as chokes to prevent ALL of the filter caps
stored energy from trying to empty into your primary circuit at once,
which cause the primary circuit to go nuclear!

David Rieben