Case Histories—Successful and Unsuccessful Application of MCSA to Estimate Operational Airgap Eccentricity in Scims

This chapter reports several case histories, which cover successes and failures of motor current signature analysis (MCSA) to assess the operational airgap eccentricity in squirrel cage induction motors (SCIMs). First case history gives a detailed presentation to illustrate that attention to detail is essential when carrying out MCSA to analyze the current to estimate the operational airgap eccentricity. Second case history reports on an MCSA test of a brand new inverter‐fed, high voltage (HV) SCIM to assess its operational airgap eccentricity during a no‐load, uncoupled run. Third case history verifies that the operational airgap eccentricity can be assessed in a large, inverter‐fed, HV SCIM via MCSA when the motor is on load. The motor drives a centrifugal compressor on an offshore oil and gas production platform. Final case history shows that MCSA was unable to assess the airgap eccentricity in a SCIM driving a reciprocating compressor.