Modern on-line testing of induction motors for predictive maintenance and monitoring

On-line testing of motors, diagnostics and motor monitoring have shown large scientific development in the past few years, outgrowing the stage of RMS current and voltage measurements. This stems from current and voltage signature analysis which has progressed from the laboratory and the work of dedicated specialist experts to become the base for modern instrumentation available to plant operatives. In addition to line fed motors, a clear view of variable frequency drive applications is now possible without requiring connection directly to the motor terminals. The use of the motor itself as a transparent sensor, making shaft torque signatures available at the motor control cabinet, allows for advanced diagnostics of the voltage supply, motor and load system.