3D magnetic field analysis using special elements

Three-dimensional special elements, called the gap element, the expanding element, and the shielding element, have been conceived for discretizing narrow gaps in an iron core, the long legs of a transformer core, and thin shielding plates. The concept of the 3D special element and its finite-element formulation are described. The special elements are applied to several models, and the effects of the elements on accuracy and CPU time are discussed. It is shown that CPU time can be reduced by using the special elements