FEM Modeling of Surface Losses in Accordance with Their Nature

The paper presents a new method to estimate the surface losses caused by the non-sinusoidal spatial distribution of the magnetic field, moving over the surface of laminated rotor cores. The rotating magnetic field present in the air gap of ac electrical machines causes additional losses, which are very important during motor design, in particular for high-speed applications. A simplified - but still consistent in its nature - finite element method model has been developed to simulate the mechanism of the surface loss generation. The obtained results are critically discussed and compared with those reported in other research works.