20 November 2020

Advantages and disadvantages of permanent magnet synchronous motor

 A permanent magnet synchronous motor (PMSM) is a device designed by using permanent magnets embedded in the steel rotor to create a constant magnetic field. This type of motor one of the best choice for a full range of motion control application. So here this article gives the Permanent magnet synchronous motor advantages and disadvantages to netter understand this topic. 

Advantages of the permanent magnet DC motor:

  • Permanent magnets are smaller in size.
  • These motors do not require any field of windings, and they do not have field circuit copper losses. This increases their efficiency.
  • For smaller rating permanent magnet which reduces the manufacturing cost and thus the PMDC motor is cheaper.
  • This motor has a low torque ripple so it can generate constant torque. Also, its ability to maintain full torque at very low speeds.
  • It has only stator winding and no rushes so its heat generation is low compared with a brush motor.
  • Do not need an extra DC power source for it. The AC supply is provided on the stator and it is the permanent magnets are on the rotor.
  • Permet magnet motor full-load efficiency is higher than the use of an AC induction motor.
  • The permanent magnet synchronous motor has not any brushes so it has a low maintenance cost.

Disadvantages of permanent magnet synchronous motor:

  • There is a  risk of demagnetization of the poles which may be caused by a large armature current.  Demagetizatiob cab also occurs due to excessive heating and also when the motor is an overload for a long period of time.
  • Extra ampere Cannot be added to reduce the armature reaction.
  • The magnetic field of the PMDC motor is preset at all times, even when the motor is not being used.
  • The permanent magnet produces a high flux density as that an externally supplied shunt field does. Therefore, a PMDC motor has lower induced torque per ampere-turns of armature current the shunt than a shunt motor of the same rating.
  • Permanent magnet motor solutions tend to need a higher initial cost than the use of AC induction motors so more difficult to starts up than AC induction motors.
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