Now, industrial fan motors are mainly divided into traditional gearbox motors (asynchronous motors) and permanent magnet （PMSM) motors, while permanent magnet motors are divided into two types of motors: inner rotor and outer rotor. The internal structure of traditional gearbox motors will use reducers and gears.
The working principle is similar as the gearbox of the car, and the gearbox oil also needs to be replaced in the later period of use. If it is not replaced, the fan motor will make a squeaking metal noise.
With advanced permanent magnet motor technology, there is no reducer and gear in the motor, no need to change the transmission oil regularly. However, the permanent magnet with outer rotor, because the stator is in the middle of the motor, will generate heat during operation, so the body of the permanent magnet motor will have a radiator, and dust impurities may enter through the gap of the radiator, resulting in the weakening of the motor’s heat dissipation performance. Increase the load of the motor, so the permanent magnet external rotor motor also needs regular maintenance and maintenance.
Compared with the outer rotor, the inner rotor of the permanent magnet motor has inherent advantages. The stator is on the periphery, and the heat during operation is directly cooled by natural wind, no other radiator is needed, and the sealing performance is good, waterproof and dustproof, except that the outer casing needs normal dust cleaning, No special maintenance is required inside the motor.
