Study of Eddy Current Losses in a Stator Steel Sheet of a Machine with Radial Stator Lamination

This paper presents finite element analysis simulations of a steel sheet for radially laminated permanent excited synchronous machine. The focus is on the path of the eddy currents and the dependence of the eddy current losses on the steel sheet length. Three different models are presented. The first model considers only the stator field, the second model only the field generated by the rotor with surface mounted magnets, and the third model considers stator and rotor field. It is shown that in all models the highest losses occur by the eddy currents in axial direction. Nevertheless, eddy currents in the steel sheet surface occur by certain rotor positions due to the stray fields. The eddy currents are not linearly related to the length of the steel sheet, so that the length cannot be scaled linearly.