The use of phase current analysis to detect faults in squirrel cage induction motors onboard military warships

Three phase induction motors are by far the most common prime mover in both industrial and marine applications. The Royal Navy is very dependent on this type of motor for driving services such as hydraulics, lubrication, steering, compressors and stabilisation etc. A failure of any of these machines could have a detrimental effect on a vessel's capability and performance as well as the possibility of withdrawal from station or failure to respond to military objectives. As well as performance and reliability issues, environmental and safety points are also discussed. The paper shows the experience given by Eleco Dowding and Mills on naval warships in conjunction with the Ministry of Defence. Two case histories are studied which show that phase current analysis is a reliable method for detecting faults.