MCSA Industrial Case Histories—Diagnosis of Cage Winding Defects in SCIMs Driving Steady Loads

This chapter presents case histories, in which the squirrel cage induction motors (SCIMs) are driving steady loads and where the identification of the ±2sf sidebands around the supply component is not being influenced by mechanical load dynamics downstream of the motor. Normal cage winding asymmetry, caused by normal differences in resistances between a number of bar to end ring joints. The SCIM was driving a strategic centrifugal compressor on an offshore oil and gas production platform operating in the North Sea off the coast of Scotland. The analysis that follows was the outcome of an annual motor current signature analysis (MCSA) survey of the HV SCIMs and is presented in considerable detail as an introductory case history. Another case history highlights a faulty cage winding and is useful as an initial learning guide and reference for an industrial engineer.