Determination of synchronous motor vibrations due to electromagnetic force harmonics

A method for the computation of magnetically induced stator vibrations in synchronous motors is presented. The electromagnetic field in the motor is calculated, and the fluctuations of the magnetic forces applied to the teeth of the stator are evaluated. The harmonics of these magnetic forces are calculated by means of a mechanical finite-element analysis, leading to determination of the motor vibrations. The method is used to compare vibrations produced by two permanent-magnet synchronous motors of different magnetic structures, one with radially oriented magnets and one with tangentially oriented magnets. The results clarify the mechanism of generation of the vibrations.<
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