8' drive on PC troubleshooting

Tue Mar 8 17:19:41 CST 2005

> Be sure to check the labels on the stepper motor. Some years ago I had a
> brief "aquintance" with a SSSD drive from Control Data. I binned it
> immediately, as it showed that the steppermotor needed 115VAC !

Never! I've enver seen am 8" drive with anything but a 24V stepper motor.

The spindle motor is often mains powered (and often 115V, to be powered 
by an autotransformer if you have 230V mains). It's a capacitor-run 
induction motor, and you generally have to change the pulleys (and maybe 
the belt) when going between 50Hz and 60Hz mains, to get the spindle 
speed right.

My P851 and P854 systems have CDC floppies (and I have the CDC service 
manual for them). They have 24V steppers and AC-line powered spindles.

-tony