Hi Guys

I have a project to control 3 small stepper motors and I am having difficulty getting them to behave. I have used larger NEMA34 motors before and had teething problems with them but ended up with a working solution. The small step motors I need to control are CKD brand, 3.75 degree, 24V, 60 ohm, model number J262-859. I have checked their website but cant find ANY info. These motors are about 40mm dia and 12mm thick. I think they are called 'can' type.

I am trying to control them with Compumotor OEM-750 drives and am using the following settings.

motors set at bipolar half winding ie I'm using one end and the centre tap of each phase

supply voltage 75V (Compumotor OEM-300)

10uStep (set as 2000 steps per rev equiv for a 200 step motor, these are 90 step ie 3.75 degrees)
current gain of 32 (default is 8 for these drives, 32 makes it turn)
working in the 0.2A to 0.7A range seems to work OKish at about 0.5A
standby set to 25%

I can get them to turn but they get hot within a few minutes (I cant hold them for more than 2 seconds) so I turn the drive off and cause my brain more pain by trying to work out why.

Any ideas on troubleshooting would be most appreciated.

derekj308