using a computer screen to test motor synhnicity..

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

Original poster: "Justin Wright by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ellis_p-at-picknowl-dot-com.au>

HI All,

I was recently testing some synch motors that I found in a second hand 
shop.  One was made by Fracmo and they finally got back to me sayingn they 
would look it up and send me the info.

The two other motors I had bought were also marked as "Synchronous".  Only 
when I got home, did I find an old pupman posting that said Hysterisis 
motors really suck.  One down, one to go.  The other was a "reluctance 
synchronous PSC" motor.

I remember reading that you could use the light from a flouro tube to 
examine the rotation.  I tried this with all sorts of bits of tape attached 
to the shaft, but I couldn't see anything.

Then I change the refresh rate of my screen to 100hz and held the motor up 
to the screen.  The piece of tape that I had stuck to the shaft had 
partially unstuck itself and was now sticking out past the end of the 
shaft.  As it wizzed around, I could the the end of the tape frozen in the 
light from the screen.  At 100hz I could see four stationary bits of tape.  
  I tried at 75hz and got 3.  When I turned the motor on and off, the 
taped locked into a different position.  bummer.

Does anyone know what a reluctance synch psc motor is?



Regards

Justin.