How does the permanent magnet variable frequency air compressor solve the demagnetization problem?
- Correctly select the power of the permanent motor. Demagnetization is related to the power selection of the permanent magnet motor. The correct selection of the power of the permanent magnet motor can prevent or delay the demagnetization. The main reason for the demagnetization of the permanent magnet synchronous motor is that the temperature is too high, and overload is the main reason for the high temperature. Therefore, a margin should be left when selecting the power of the permanent magnet motor. According to the actual situation of the load, generally about 20% is more appropriate.
- Avoid heavy load starting and frequent starting. The cage-type asynchronous start synchronous permanent magnet motor should try to avoid direct starting or frequent starting under heavy load. In the process of asynchronous starting, the starting torque is oscillating, and in the trough section of the starting torque, the stator magnetic field demagnetizes the rotor magnetic poles. Therefore try to avoid the heavy load and frequent starting of the asynchronous water magnetic synchronous motor.
- Improved design.
- (1) Appropriately increase the thickness of the permanent magnet. From the perspective of permanent magnet synchronous motor design and manufacture, the relationship between armature reaction, electromagnetic torque and permanent magnet demagnetization should be considered. Under the combined action of the magnetic flux generated by the torque winding current and the magnetic flux generated by the radial force winding, the permanent magnets on the rotor surface are likely to cause demagnetization. Under the condition that the air gap of the motor remains unchanged, the more effective method to ensure that the water magnet does not demagnetize is to increase the thickness of the permanent magnet appropriately.
- (2) There is a ventilation groove circuit inside the rotor to reduce the temperature rise of the rotor. An important factor affecting the reliability of permanent magnet motors is the demagnetization of permanent magnets. If the temperature of the rotor rises too high, the permanent magnet will lose its magnetism irreversibly. In the structural design, the internal ventilation circuit of the rotor can be designed to directly cool the magnetic steel, which not only reduces the temperature of the magnetic steel, but also improves the efficiency.
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