On-line current monitoring to detect rotor winding and electromechanical problems in induction motor drives

To prevent the unexpected failure of large three-phase induction motors, it is necessary to detect fault mechanisms at an early stage when the motor is still in service. This requires the use of reliable, online, diagnostic monitoring systems to detect the problems and thus enable a repair to be carried out at a convenient time to avoid disruption to production requirements. The repair can also be planned when the manpower and component parts are available. An online condition based maintenance strategy can thus avoid costly failures and potentially hazardous conditions. This paper concentrates on the application of current monitoring to detect rotor winding and electromechanical problems in induction motor drives. Reference is also included on the analysis of the current signal to indicate purely mechanical problems in the drive system.