3-D Magnetic field analysis by using special elements

3-D 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 the thin shielding plates. The concept of the 3-D special element and its finite element formulation are described. The special elements are applied to a few models and the effects of these elements on accuracy and CPU time are discussed. It is shown that CPU time can be reduced by using the special elements.