permanent motor magnet

Correct selection of permanent magnet motor power   Demagnetization is related to the power selection of the permanent magnet motor. Correctly selecting the power of the permanent magnet motor can prevent or delay demagnetization. The main reason for the demagnetization of the permanent magnet synchronous motor is excessive temperature, and overload is the main reason for excessive temperature.   Therefore, when selecting the power of the permanent magnet motor, a certain margin should be left. According to the actual load situation, about 20% is generally more appropriate.     Avoid heavy load starting and frequent starting   Cage-type asynchronous starting synchronous permanent magnet motors should avoid heavy-load direct starting or frequent starting.   During the asynchronous starting process, the starting torque is oscillating. In the starting torque trough section, the stator magnetic field has a demagnetizing effect on the rotor poles. Therefore, try to avoid heavy-load and frequent starting of asynchronous permanent magnet synchronous motors.   Improved design   1. Properly increase the thickness of the permanent magnet   From the perspective of permanent magnet synchronous motor design and manufacturing, the relationship between armature reaction, electromagnetic torque and permanent magnet demagnetization should be considered.   Under the combined effect of the magnetic flux generated by the torque winding current and the magnetic flux generated by the radial force winding, the permanent magnet on the rotor surface is prone to demagnetization.   In the case of the motor air gap remaining unchanged, the most effective way to ensure that the permanent magnet does not demagnetize is to appropriately increase the thickness of the permanent magnet.   2. There is a ventilation slot circuit inside the rotor to reduce the rotor temperature rise   If the rotor temperature rises too high, the permanent magnet will lose its magnetism irreversibly. When designing the structure, a ventilation circuit can be designed inside the rotor to directly cool the magnetic steel. This not only reduces the magnetic steel temperature, but also improves efficiency.