Permanent Magnet Machines

This chapter aims to relate the operational requirements of permanent magnet (PM) motors to their dimensions, shapes, and material properties. It describes how the physical dimensions and parameters are influenced by PM excitation. The chapter summarizes the major parameters of the motor circuit model. It shows the conventional steady‐state equivalent circuit for a PM motor. In this representation, the MMF produced by the magnet is represented as a current source I
_f
. The surface‐magnet machine is only one of a wide variety of magnet configurations used for PM machines. Structurally, this construction can provide a more secure magnet setting. The motor can also produce somewhat more maximum torque and its overspeed range is larger due to its saliency. The largest family of PM machine involves those with buried magnets. The chapter shows some of the possibilities. It discusses several typical examples of these machines to illustrate the issues involved.