Signature Analysis for Online Motor Diagnostics: Early Detection of Rotating Machine Problems Prior to Failure

The Stator-current signature analysis of induction motors is a proven method to diagnose rotor squirrel-cage winding defects and air-gap-eccentricity problems. With this technology, specific frequency-current components can be identified as an indication of cage-winding defects as well as a nonuniform gap between the stator and rotor. Since these data are generally collected periodically, it is important to identify the components as early as possible. The trendable parameters can then be monitored more often to avoid in-service failure. With the application of new processing technologies, the ability to identify these critical current-signature frequency components and trend the deterioration that they indicate has improved. This allows for maintenance activities to be scheduled earlier and performed prior to failure, avoiding costly motor component damage and unplanned downtime.