To confidently report the electrical condition of a motor, there are six areas of interest known as Fault Zones that must be looked at during the troubleshooting effort.
These Fault Zones are Power Quality, Power Circuit, Stator, Insulation, Rotor, and Air Gap.
Power Quality:
Quality of the voltage and current
Stator:
Turn-to-turn insulation and internal coil connections
Air Gap:
Quality of the air gap between the rotor and the stator
Insulation:
Winding to ground insulation
Rotor:
Health of the rotor cage and laminations
Power Circuit:
Circuit supplying power to the motor
This insightful white paper by PdMA’s David L. McKinnon will provide a brief introduction to a Six Fault Zone approach for predictive maintenance on motors.