The main indexes of NdFeB permanent magnet have a great influence on the performance of motor

The magnetic index of NdFeB permanent magnet directly affects the performance of motor. Remanence force, coercivity (intrinsic coercivity), maximum magnetic energy product and Curie temperature are the most important performance indexes of NdFeB magnet.

The remanence index is the maximum magnetic flux intensity that the magnet can provide after magnetization without external magnetic field. The larger its value is, the higher the magnetic density in the magnet air gap, and the higher the maximum torque and maximum efficiency point.

Coercivity is a parameter indicating the ability of the magnet to resist demagnetization. The greater its value, the lower the thickness of the magnet and the stronger the ability to resist overload;

The maximum magnetic energy product represents the maximum magnetic energy that the magnet can provide externally. The higher its value, the less magnets are used at the same power.

Curie temperature TC is the temperature point at which the magnet magnetism disappears, which represents the temperature range in which the magnet can work.

The temperature coefficient a represents the percentage of reversible change of magnet magnetism with temperature change. These two indexes are the temperature indexes to be considered when using magnetic materials.

In addition, the shape of the magnet also has a great impact on the performance of the motor. The thickness, width, chamfer and other shape conditions of the permanent magnet can not only affect the efficiency of the magnet, but also affect the accuracy of the mechanical installation of the magnet and the vibration in use, and ultimately affect the efficiency and cost of the motor.

When the external magnetic circuit of the motor is fixed, the increase of magnet thickness can reduce the air gap and improve the efficiency of the motor, but it will lead to the commutation vibration of the motor. If the square magnet is not chamfered, it will cause a large change rate of magnetic field and lead to the pulse vibration of the motor. The larger the chamfer, the smaller the pulse vibration; However, the chamfer will result in less magnetic flux.