Lateral Vibration Created By Torsional Coupling Of A Centrifugal Compressor System Driven By A Current Source Drive For A Variable Speed Induction Motor.

A serious radial gear vibration was determined to be caused by significant torsional excitation from a squirrel cage induction motor that was controlled by a variable frequency current source inverter drive. Field test data verified and quantified the frequency and magnitude of torque due to interharmonic distortion and ultimately provided data to verify that system modifications had eliminated the gear vibration and verified suitability of the system for long term variable speed operation.