The Ferrite Permanent Magnet AC Motor---A Technical and Economical Assessment

The design and analysis study for the conceptual design of an economical high-efficiency ac motor based on permanent magnets is summarized. Material considerations, design trade-off options as well as transient and steady-state performance under normal and abnormal conditions have been considered. The baseline comparison is the high-efficiency induction motor. The permanent magnet (PM) motor must fit into the same frame size and surpass the induction motor on a life cost basis that includes 2.5 years of operation at a 50 percent duty cycle. The study results indicate that a motor with ferrite magnets meets the objectives of the program in ratings of up to 25 hp. A 7.5-hp motor design is carried through the conceptual design stage.