Original poster: Steve Ward <steve.ward@xxxxxxxxx>
I told Christopher this on the phone as well, but would like to convey
my thoughts on the list. I think that an MMC is probably the best way
to go for such a cap. It seems that MMCs offer very high RMS and peak
current ratings for the type of cap arrangements that would be used in
DRSSTCs (usually 6-10kV rating, but several times larger capacitance
than a similarly sized SGTC). In fact, for this 48kVA coil i think
Jimmy Hynes and myself were thinking something around 2-3uF (thats not
a typo). My largest DRSSTC uses a .5625uF cap for 12' sparks, so id
imagine to double that spark length, something around 4X the
capacitance would be required. And if we are going for say 30' max,
we might need a bit more. But really, i think the usable range is
very wide and not all that critical aside from affecting other design
considerations (but basically, pick a value and work the rest out from
that). You could imagine that an MMC built for a few uF will need
many many parallel strings, so the peak and RMS ratings will be *very*
high. Expecting peak currents of only 3-4kA, but the RMS will be very
high (havent actually calculated it yet, but in the hundreds of amps
easily). MMC is the way to go!
Steve