If permanent magnet synchronous motor manufacturers ask you how the motor works, can you answer? In fact, it is very simple. Although there is no direct electrical connection between the motor rotor the stator, when the stator winding is electrified, there is an electromagnetic connection between the stator the rotor through the air gap. Similar to the transformer principle, the stator magnetic field the rotor magnetic field are coupled with each other, thus realizing the energy conversion function between the electric energy the mechanical energy.
In fact, there are three kinds of noise in the motor: air noise, mechanical noise electromagnetic noise.
1. Reasonable design of motor structure
(1) Correct selection of fan material structure: for unidirectional high-speed motor, streamline backward inclined centrifugal fan can be used. For centrifugal fan, the noise with reverse ring is lower than that without reverse ring; in addition, the noise of basin fan is lower than that of blade fan; the noise of aluminum fan is lower than that of nylon fan.
(2) The air gap can be properly increased to reduce the air gap magnetic density when the motor in use produces "sweeping". When the power of the motor is sufficient, the rotor can be turned around to increase the air gap eliminate the noise caused by high-order harmonics. However, the no-load current is increased the power factor is reduced at the same time.
2. Ensure good assembly process
(1) high quality bearings. The fit between the bearing the shaft between the bearing the bearing seat shall be proper, the temperature time of the bearing hot sleeve shall be well controlled.
(2) The poor dynamic balance of rotor is the main cause of mechanical noise, so it is necessary to improve the accuracy of dynamic balance test of rotor, minimize the impact of eccentricity, ensure the concentricity of coupling during motor installation.