What are the disadvantages of permanent magnet (PM) motor?

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cs asked 5 years ago

I need short information.

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cs answered 5 years ago

The disadvantages of permanent magnet (PM) motor are:

  1. Since, high-energy rare earth PMs are used, machine cost is much higher than the induction counterpart.
  2. As the PMs are located in the rotor, it has a problem of high-speed operations.
  3. Because of uncontrollable PM flux, the constant-power operation range is limited.
  4. In case the machine is not properly designed or operated, the PMs may be accidentally demagnetized by high armature reaction field or under high operating temperatures.