Signature analysis for on-line motor diagnostics

Stator current signature analysis on induction motors is a proven method for diagnosing 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 non-uniform gap between the stator and rotor. Because this data is generally collected periodically, it is important to identify these components as early as possible. These trendable parameters can then be monitored more often to avoid inservice failure. With the application of new processing technologies, the ability to identify these critical current signature frequency components and trend the deterioration 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.