Vibration analysis considering higher harmonics of electromagnetic forces for rotating electric machines

A method is described to calculate vibration due to electromagnetic forces for rotating electric machines. This method can calculate the frequency response of vibration due to higher harmonics of electromagnetic forces. The usefulness of this method is verified through the agreement between calculated and measured results for a three-phase/four-pole induction motor. The authors also calculate the complicated dynamic behavior caused by eccentricity, that is, the difference of the stator axis and the rotor axis.