ABSTRACT

The magnetic circuit is an important active part of transformers, which transfers electrical energy from one circuit to another. It is in the form of a laminated iron core structure which provides a low reluctance path to the magnetic flux produced by an excited winding. Due to research and development efforts by steel and transformer manufacturers, materials with improved characteristics have been developed and employed with better core building technologies. The magnetic path consisting of the end yoke and the end limb has higher reluctance than that of the main yoke. An analytical formulation based on the finite difference method is used in to calculate the spatial flux distribution and core loss. The method takes into account the magnetic anisotropy and nonlinearity. The measured power losses for ferromagnetic materials are usually two or three times the value calculated by using the classical eddy current theory.