Troubleshooting Weak Stepping Motors | Tips for Maintaining Optimal Performance

[alhughes]

Where I work we have 12 amp 1.8 degree stepping motors, occasionaly a motor will go weak, we change motors and all is good, when i strip the motors to check, the bearings are fine, the windings are fine, correct resistance, no insulation breakdown to Earth or between windings, so what causes the weakness? the only thing I can't check is the magnetism of the rotor, any clues?

 

[fleem]

A possibility is a single shorted turn or two. That can soak up a lot of energy but not change the resistance much.