Deformation Analysis of Induction Machines by Means of Analytical and Numerical Methods

The estimation and calculation of the acoustic sound of electric machinery is of high interest. Various approaches have been presented relying either on analytical or on numerical models. In general, the analytical models are based on the electromagnetic-field theory, and the results are compared to measurements. Numerical models allow for the separation of different exciting forces stemming from various effects. In the studied case of an induction machine (IM) with squirrel-cage rotor the three following effects are taken into account in the analytical model: the fundamental field, saturation, and eccentricity. Nevertheless, the numerical results have to be verified. Hence, they are compared to the physically based analytical results. The radiated noise depends directly on the surface´s deformation of the machine. Therefore, the analysis is focused on the structure-dynamic vibrations. The combined analysis presented here, allows for the reduction of vibrations and noise optimizing the coupling of stator and housing. The studied IM´s housing is mounted with six spiral-steel springs to the stator. With the presented method the impact of different numbers of pins is analyzed.