Transient rotor fault detection in induction and synchronous motors

摘要

To detect broken bars in the rotor of induction and synchronous motors, the current drawn by the motor during the transient startup period as the motor runs up to steady state speed is analyzed to identify any dip in the starting motor current amplitude occurring when the motor reaches approximately half-speed. The magnitude of any identified current dip is tested against threshold values to determine if the dip is characteristic of a broken rotor bar condition. Reliable broken rotor bar detection is achieved regardless of whether the motor is loaded or unloaded.