I was trying to test a stepper motor for specified holding torque by applying the proper current (5 amps) to the windings from a constant current power supply. I found that it held within tolerance in one direction, but when attempting to break the hold in the opposite direction, the force required was about 30% less. Any ideas why it would have more holding torque in one direction than the other? My only thought was that going one direction, the generator effect was adding voltage to the source and in the other, it was subtracting voltage. Even with that theory, the constant current supply should have adjusted for the change....right?
Any thoughts are appreciated.
Any thoughts are appreciated.