Magnetic noise of induction motors

A digital computer program is described which predicts the acoustic noise generated by the magnetic field in an induction motor. The motor air gap may have static or dynamic eccentricities, and the squirrel cage rotor may be skewed or unskewed. Besides calculating the sound power in decibels at any motor speed, other important performance parameters such as steady and harmonic (cogging) torques, magnetic side pulls, currents, and the variation of the magnetic field along the stack are computed. The sound power spectrum predicted for a particular motor is compared with laboratory measurements.