RL02s available - test-drb@ccmp.vtda.org

15 Oct 1999

On Oct 15, 19:18, Tony Duell wrote:

...
  > Now I've never used a RL02 drive on 50Hz
power, but I'm 99% certain that
...
   the motor
speed in a RL02 is determined by a servo loop, and thus
 not locked to a multiple of the AC frequency. 
 Currect. From the RL01/RL02 Technical Manual :

 'RL01/RL02 drives are shipped from the factory as 115Vac/60Hz units.
 Field change to 230Vac 50 or 60Hz is acoomplished by reversing either of
 two terminal block covers located externally at the rear of the drive. 
...
  The RL drives run the motor at considerably below
synchronous speed. They
 control the motor speed with a couple of triacs on the AC Servo Module,
 and measure the speed (IIRC) using the sector pulse timing. That's why
 the disk spins _very_ fast if you forget to plug the transducer in... 
Or if the AC servo board goes in certain ways, as I discovered in one of a
pair I got from Heriot-Watt University: the local DEC engineer had at some
time in the dim and distant passed fixed one drive by swapping the AC servo
for one that was rarely used.

-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York