Equivalent Circuit and Evaluation of Eddy-Current Loss in Solid Cores subjected to Alternating and Rotating Magnetic Fields

In the study of eddy-current distribution in solid cores subjected to a pulsating or rotating magnetic field a general 2-dimensional current distribution exists and is created by a magnetizing winding that restricts the current flow through it in only one direction. Under such situations, the method of evaluation of the equivalent impedance of the system as a whole is difficult to visualize and has not so far been attempted in the literature. Such an evaluation calls for a concept of the power factor of the magnetizing winding. This is the special feature of the paper. The paper further examines the usefulness of this concept for the evaluation of eddy-current loss in solid cores and thus offers an alternative method. To give more validity to several of the formulae deduced in the paper, the analysis is applied to compute the performance characteristics of a solid-rotor induction machine and certain conclusions are drawn.