MAJOR DESIGN PARAMETERS OF A SOLID CANNED PERMANENT-MAGNET MOTOR WITH SKEWED MAGNETS

Permanent magnets buried in the rotors of synchronous machines are now accepted as a means of producing a high performance machine which can take advantage of rare earth magnets. The magnets can with advantage be nonradial, but an alternative strategy is to use radial magnets with a significant skew. It will be seen that this arrangement leads to a drastic reduction in harmonics and cogging torques. The use of a supporting tube on the rotor whether magnetic or not, is also investigated with a view to overcoming problems of high-speed operation.