Analysis and design considerations for permanent-magnet aerospace-instrument devices

Abstract

The range of permanent-magnet materials for electro-magnetic-device applications has recently been augmented by the commercial development of Samarium Cobalt. Of particular importance is the magnetic characteristic of SmCo 5 in relation to other available hard magnetic materials. The most striking aspects of the material are its high coercivity and possible maximum energy level, while the most gratifying aspect is its predictable performance. In order to make best use of a high quality and relatively expensive magnetic material such as SmCo 5 , one should strive for optimized designs. In view of the complicated geometries involved, significant leakage flux particularly caused by compact design, and nonlinear ferromagnetic materials used in making up the electromagnetic device, it becomes necessary to resort to numerical solutions to determine the effect of variation of significant parameters involved and to achieve an optimized design for the device. The paper presents the modeling techniques for simulating permanent magnets in computer-aided analysis, methods to deal with various geometries and inherent symmetry that may be a characteristic of the problem. By numerically analyzing the model, detailed flux-distribution plots have been obtained by means of a high-speed digital computer. The paper discusses typical cases that have been studied.