Permanent magnet synchronous motors

There are many configurations of permanent magnet machine, some of them are more significant than others. Machines are most commonly 3-phase but single phase capacitor start and run designs can be very effective. There is an ever widening choice of magnet materials available, but the most useful are the ferrites and the rare earths, whether samarium cobalt or neodymium-iron-boron. The choice of magnet depends on the specification, with initial cost and operating temperature having an important role. The author examines motor characteristics for three types of permanent magnet synchronous motors and assesses the cost effectiveness of each type