The magneto rotor is composed of magnetic steel, metal shaft or metal shell. According to the specific application, the rotor magnet can be sintered, molded or injection molded with NdFeB magnet materials and multipolar magnetic ring ferrite magnet materials. It can be used for high-speed motor, linear motor, stepping motor, etc.
With the improvement of the properties of permanent magnetic materials, rare earth permanent magnetic materials have been widely used in the electrical field. The motor is made of high-performance rare earth permanent magnet materials, and the structure does not require a special electric excitation system, which helps to improve the efficiency and power factor of the motor, save energy, and reduce the size of the motor. At present, in the design of permanent magnet motors, it is generally assumed that the uniform distribution of the magnetic field of each part of the permanent magnet and the magnetic characteristics of the same batch of permanent magnets can be the same, although the supplier of the permanent magnet at room temperature, inherent connectivity magnetic parameters, remanence, density and maximum energy product of the permanent magnet that needs to use the demagnetization curve of the permanent magnet are required.
However, due to the manufacturing process and factory level, each part of the permanent magnet has a temperature, so the actual performance is different, and the performance of the same group of permanent magnets is also different.
The magnetic properties of permanent magnet are closely related to the magnetic rotor during normal operation, and the reliable operation of permanent magnet motor directly determines.
When a permanent magnet motor is running, it sometimes leaves an irreversible demagnetization phenomenon of NdFeB with high rotor temperature, which leads to deterioration of performance indicators such as efficiency and power factor of the permanent magnet synchronous motor.
