Permanent magnet synchronous motor is mainly composed of stator, rotor and shell components. Like the common AC motor, the stator core is laminated structure to reduce the iron loss due to eddy current and hysteresis effect. The winding is usually a three-phase symmetrical structure, but the parameter selection is quite different. The rotor part is in various forms, there are permanent magnet rotor with starting squirrel cage, and there are built-in or surface mount pure permanent magnet rotor. The rotor core can be made of solid structure or laminated. The rotor is equipped with a permanent magnet material, which is commonly called magnetic steel.
Under normal operation of the permanent magnet motor, the rotor and the stator magnetic field are in a synchronous state, the rotor part has no induced current, no rotor copper consumption, hysteresis, eddy current loss, and there is no need to consider the problem of rotor loss and heating. General permanent magnet motor for the special inverter power supply, naturally has a soft start function. In addition, the permanent magnet motor is a synchronous motor, which has the characteristics of adjusting the power factor through the excitation strength of the synchronous motor, so the power factor can be designed to the specified value.
From the perspective of starting, the starting process of the permanent magnet motor is easy to realize due to the fact that the permanent magnet motor is started by the frequency conversion power supply or the supporting frequency converter. Similar to the starting of variable frequency motor, the starting defect of ordinary cage induction motor is avoided.
However, the loss of magnetic fault is an unavoidable problem of permanent magnet motor, when the current is too large or the temperature is too high, it will cause the motor winding temperature to rise instantaneously, the current increases sharply, and the permanent magnet rapidly loses magnetism. In the control of permanent magnet motor, the overcurrent protection device is set to avoid the problem that the stator winding of the motor is burned, but the magnetic loss and equipment outage caused by this are inevitable.
Compared with other motors, the application of permanent magnet motors in the market is not very popular, whether for motor manufacturers or users, there are some unknown technical blind spots, especially when it comes to the matching problem with the inverter, which often leads to a serious mismatch between the design value and the test data, and must be repeatedly verified.
Guangdong South Magnet Technology CO.,Ltd is a professional manufacturer of magnetic products and magnetic material with magnetic circuit design in 20 years. Welcome to come to us for more information.
Beam Zheng :+86-13702311005 [email protected]
