Electro-mechanical analysis of the audible noise of inverter-fed squirrel-cage induction motor

The audible noise emitted by a three-phase squirrel-cage induction motor fed by a frequency inverter is determined by the electromagnetic and mechanical behavior of the components of the drive. A computerized analysis method is described which uses theoretical as well as experimental data for predicting the audible noise spectrum components. Starting from the inverter voltage and the motor data, the electromagnetic forces are predicted and analyzed. The mechanical natural frequencies are considered, either in a theoretical (finite-element calculation) or in an experimental (modal analysis) methodology, in order to predict the vibrational behavior of the machine.<>