3-D Finite Element Analysis of Additional Eddy Current Losses in Induction Motors

In this paper, an approach based on the three-dimensional finite element analysis is proposed to evaluate additional eddy current losses in induction motors of several MW. Losses produced by induced eddy currents in the end-region of the machine (stator clamping-plates and clamping-fingers) and losses provoked by parasitic leakage fields in the housing and in the metal parts of the cooling-ducts are investigated. Furthermore, excess rotor copper losses produced by higher harmonic fields in the rotor squirrel cage are taken into consideration as well. Comprehensive three-dimensional finite element models have been prepared in order to take these effects precisely into account. A numerical procedure based on nonconforming finite element meshes has been used in order to simplify the modeling procedure and the solving process has been carried out in the frequency domain with the aim of reducing the computational time.