There are many kinds of permanent magnet materials, and their performances vary greatly. Therefore, in the design of permanent magnet motor, it is necessary to select the appropriate permanent magnet materials and specific performance indexes.

1、 Principle of choice

(1) It shall be able to ensure that there is enough air gap flux density and specified motor performance index in the air gap of the motor;

(2) The stability of magnetic properties shall be guaranteed under the specified environmental conditions, working temperature and service conditions;

(3) Have good mechanical properties to facilitate processing and assembly;

(4) The economy is good and the price is suitable.

2、 Description (according to the performance of the existing permanent magnet materials and the performance requirements of the motor, there are the following descriptions)

(1) With the continuous improvement of performance and the gradual reduction of relative price, NdFeB permanent magnet materials will be more and more widely used in the motor. It is not only possible to replace other permanent magnet materials in some occasions, but also to gradually replace the traditional part of the electric excitation motor.

(2) In the case of high demand for performance and reliability but not the main factor of price, the 2:17 rare earth drilling permanent magnet material with high coercive force is preferred. The application of 1:5 rare earth cobalt permanent magnet material will be reduced, mainly used in high temperature and demagnetization field

(3) For the general performance requirements, the volume and mass restrictions are not strict, and the price is the main factor to be considered, the ferrite permanent magnet material with low price is preferred.

(4) When the working temperature is over 300 ° C or the temperature stability is strictly required, such as motors for various measuring instruments, aluminum nickel cobalt permanent magnet materials with low temperature coefficient are preferred. The proportion of aluminum nickel cobalt permanent magnet materials in the total permanent magnet materials will gradually decrease.

(5) In the case of large batch production and complex pole shape, bonded permanent magnet materials are preferred.

The specific selection should be determined after comprehensive analysis and comparison of performance, process and cost of various schemes.