Phase control testing

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Esondrmn-at-aol-dot-com>

Well, I finally got enough caps to get my phase control set up working for my 
sync rotary gap.  Thanks to Bert Hickman for selling me one of his caps. 
Again, I have a 3,600 rpm synchronous GE motor, 1/3 H.P.  I am using a 10 amp 
variac with the caps for the phase control set up.  I had to go to 250 ufd to 
get the voltage across the motor to hold relatively constant.  Any less and 
the voltage would decrease below the sync lock point, which is 110 volts, 
when the variac was adjusted to near the max setting.  The voltage across the 
motor now starts at 125 v with the variac set at zero, it is 130 v at about 
50% variac setting and goes down to 124 v at full variac setting.  The 
current in the capacitor leg starts at 11.5 A, goes up to 14.3 A then down to 
12.1 A at full variac setting (blowing my 10 A fuse, which was changed to a 
paper clip).  The current into the motor is 7.8 A with the variac set at 
zero, goes up to 10.7 A at mid point then down to 7.7 A at full variac 
setting.  The line current starts at 4.6 A, goes to 4.5 A then back to 4.6 A 
at full setting.  The line current is 8.1 A with no capacitors in the circuit.

The 250 ufd number comes out close to what Brian Basura suggested (270 ufd) 
for this motor on his post of 1-9-01.

It seems that this configuration should work.  I don't know how much phase 
angle adjustment I am getting as I don't have a 60 hz strobe.  I will try 
some LEDs running off another variac and turn out the lights and see if I can 
see anything.  Then I plan to test it on my small coil again - running at 240 
bps, then transfer it to my larger coil for testing this summer - need some 
better weather.

Ed Sonderman