Among the electrical machine users and designers, strong interest is shown to reduce the core losses at the design stage. Therefore, a rigorous analysis of the electromagnetic behavior is needed to fulfill such a purpose. Rotational power loss can contribute by a significant amount of the total core losses and, thus, has to be given a thoughtful attention. Mathematical models have been emerging to account for these losses. Yet, these models require validation by measurements and the loss phenomena have to be thoroughly studied. Measuring difficulties are often encountered due to many complications associated with the phenomena.This thesis investigates experimentally the power losses using a modern measuring system in one- and two-dimensional magnetic fields. A measurement technique for rotating flux and magnetic field strength components in electrical steel sheets is presented. The behavior of the power losses in the sheets for one- and two-dimensional excitation fields is studied. A comparison of the power losses under different excitation fields and frequencies is presented. The measuring setup allowed the flux density to reach high values in the used material (By=1.85 T and Bx=1.72 T).
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