An investigation into damper winding failure in a large synchronous motor

This paper deals with operational issues related to a 36-MVA, 11-kV synchronous motor used to drive a reciprocating compressor in a process industry. Extensive damage to the motor's damper winding was discovered during routine maintenance. The paper identifies possible operational issues that are believed to have contributed to the development of fault, presents a simplified analytical model of the damper winding and makes recommendations aimed at identifying similar failures at an early stage.