Rotor Fault Detection in Inverter-Fed Induction Motors Using Speed Analysis of Startup Transient

Fault detection of rotatory machinery under nonstationary conditions is a topic increasing importance in industrial applications. Induction motors are not the exception and monitoring electric motor current has become a standard option to determine the health of several motor parts. However, in the inverter-fed motor case, the health condition of a motor is difficult to diagnose from electric motor current in certain cases. This paper explores the analysis of instantaneous speed during startup transient operation as a way to enhance the reliability for rotor fault detection. An experimental study of a rotor fault time-frequency evolution is presented. Results are promising and show high potential to overcome some important drawbacks of the classical current signature analysis to track fault-related signatures.