Re: MMC for 4 pack MOT supply

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

Original poster: "Sean Taylor by way of Terry Fritz <twftesla-at-qwest-dot-net>" <taylorss-at-rose-hulman.edu>

> I've been using a fixed multi gap but when I tried a sync motor at 
> 1800 RPM, two fixed electrodes and two rotating, I got nothing. 

1800 RPM and 2 electrodes??? That's only 60 bps, unless you have the
fixed electrodes at 90 degrees apart, they are parallelled, and run
from one side of the disc to the other (I guess that would be 4 fixed
electrodes?).  Anyhow, am I misunderstanding how you have your SRSG
set up? 

> This same RSG worked with an NST, but dosen't work with MOT's. I've 
> tried .01 gaps but it only fires when the motor is switched
> off and the rotor slows way down.  Any ideas.

MOTs don't have near the current limiting NSTs do, and the phase of
the voltage is thrown off because of them.  The phase of the SRSG
might have been correct to line up with a peak, or at least some
voltage of the NST, but not for the MOTs.  As the motor slows, the
phase is continuously changing, so it will eventually end up firing
when the electrodes meet and there is voltage stored in the cap.

You need to have a 120 bps rotary gap to get more performance and not
suck a whole lot of power from the AC line, as well as be able to
adjust the phase of the RSG to match with the peaks of the voltage on
the cap.

Sean Taylor