I cut the previous posts off, hope you don't mind. Your motor name plate indicates 1780 rpm? Then it is an 1800 motor with a "slip factor" counted.If it were me, I would have the rotor machined with flats on two sides to "lock" the motor to 1800 rpm and run a synchronous gap. I have heard this can be accomplished with a side grinder.
Now you can build a phase adjuster with a small variac and an experimentally valued capacitor.
I built my phase adjuster with a 400 hz variac because i had one, and it works just fine.
The main problem that I have had with the synchronous gap is blowing up capacitors,
and almost destroying my nst because I ran it exactly at resonance. Live and learn Marko kc5gym@xxxxxxx _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla