Re: Help with making SRSG phase control work?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Esondrmn@xxxxxxx 

Scott H. sent me a message inquiring if I really had a salient pole 
Oriental Motor.  He said the company tells him that they have never 
made any salient pole motors.  The data sheet actually says "Reaction 
Synchronous Motor".  So maybe it is a hysteresis motor after all?  I 
clearly have salient pole written in my notebook - maybe it was 
advertised that way from C & H Sales.  I can't absolutely testify 
that it starts in the same place everytime.  It is 1,800 rpm and I 
use a rotor with 8 electrodes at 240 bps so perhaps I would not know 
the difference.

Ed Sonderman

In a message dated 1/24/2006 11:46:22 AM Pacific Standard Time, 
tesla@xxxxxxxxxx writes:
Original poster: Esondrmn@xxxxxxx

Phil,

I am using an Oriental Motor purchased from C & H Sales.  Salient
pole, 1,800 rpm, 1/25 H.P.  It has several wires coming from the
motor, so you can reverse direction.  For discussion, let's say it
just has three.  #1 and #2 to to the AC line and there is a 3.0 ufd
400 volt capacitor connected from #2 to #3.

So you want to add a capacitor directly across the AC line terminals
at the motor (#1 & #2 above) and use the variac, center terminal and
one end as you described, in series with the AC line coming in.  You
will need to do several tests, trial and error, to select the right
capacitor.  It depends on your variac and the motor.  I am using a
10A variac.  You want to see about a 5 volt resonant voltage rise on
the input to the motor over the full range of the variac.  For my set
up, the capacitor selection was very critical.  I ended up with 17.86 ufd.

My large coil uses a 1/2 H.P. motor and a 10 amp variac and 254 ufd
of capacitance.

Good luck,

Ed Sonderman