On-line current monitoring to detect electrical and mechanical faults in three-phase induction motor drives

To prevent the sudden failure of a large motor which can be very costly and potentially dangerous, it is essential that fault mechanisms are detected at an early stage while the machine is still in service. It is therefore beneficial to have an on-line monitoring system to detect incipient trouble and thus enable planned preventive maintenance or repair to be carried out. Here, the author presents study results which show that online spectrum analysis of motor current can be used to detect broken rotor bars, dynamic eccentricity and purely mechanical malfunctions such as rotor misalignment or a worn pump in induction motor drive systems