Thanks Gary, That makes sense. The 180v was only a guess from loadpoint. If I power up the motor from this driver at say 50v and then measure the speed compared to the design max speed can I calculate the actual voltage? I always presumed the speed was due to the PWM frequency. Do you have a suitable driver? and if so how much?

Ross77,
Have you tried that motor or actually know it runs as from the picture of the er11 collet shows a lot of glass slurry and that stuff is a killer if it gets near ant rotating shaft or bearing. Best to check before you part with the readies for a driver.

peter
Very good point. didnt even think about that. Need to build a PSU to test it then. is there any way I can accurately check for play without powering it up. Ive done the obvious checks by hand and it feels smooth with no sign of radial or axial play.

Thanks