Rotary spark gaps

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

Original poster: "makinglightning comcast by way of Terry Fritz <twftesla-at-qwest-dot-net>" <makinglightning-at-comcast-dot-net>

I am building a rotary spark gap and was wondering which of 2 directions
that I should go.

I have a 1hp 24vdc permanent magnet motor with a 1/2" x 11" wheel with 14
electrodes that I have not mounted yet, which spins up to 2000 rpm (rated).
That would give me 460 bps.

I also have a 1.5 hp 90vdc pm motor that spins up to 6700 rpm (rated). I was
thinking of a .187" x 7" that I am about to route, with 6 electrodes. That
would give me up to 600 bps.

I will vary both of these with a variac.

I am not sure which way I should head in. I know that maybe I might have
balancing problems with the faster one? It would be a smaller package though
and would not require a transformer. But maybe 460bps might be just fine
with the slower motor? Would the faster one run cooler maybe? What power
levels could I go up to with brass bolts? I have heard that they would be
less likely to melt down than other types of bolts. Maybe I won't need
tungsten carbide in the wheel, less work, easier to balance. Should my
stationary electrodes be very big brass bolts or 3/8" carbide bits? Are
there any plusses and minuses to these two motor approaches that I am not
thinking of?

If anyone wants to give me their 2 cents on any of this, I would greatly
appreciate it.

Kevin