The motor can work smoothly and quietly is the goal of every motor manufacturer, but it often causes complaints because of the noise of the motor. So how to suppress motor noise is a problem to be solved.
The noise of motor can be summed up as electromagnetic noise, mechanical noise and ventilation noise.
Mechanical noise: machanical noise can be basically defined in the manufacturing process. Its characteristic is that it has the simultaneity with the motion of the motor, but it has no direct relation with whether the power is broken.
Ventilation noise: ventilation noise is mainly due to the design of the wind road, cutting off the wind road, the noise will be significantly reduced or even eliminated.
Electromagnetic noise: It is a relatively complex noise, which has a certain relationship with the design and later manufacturing. The electromagnetic noise is also related to the vibration characteristics of the stator and rotor itself, such as natural frequency, damping mechanical impedance, and acoustic characteristics and so on.
So in order to suppress the noise of motor, there are some methods.
For asynchronous motors, the proper number of stator slots and rotor slots must be selected first. The number of rotor slot is quite different from the number of stator slot, and the electromagnetic noise is smaller.
The slot slope is also an important factor for suppressing the noise of motor. For slotted motor, the skewed slots can make the dadial direction shift along the axis of the motor, thus reducing the axial mean radial force, thus reducing the noise. If the double skewed slots structure is used, the noise reduction effect is better.
Winding type: In order to reduce the harmonics of magnetic flux potential, double short moment windings can be used, and the fractional slot windings are avoided. Sinusoidal winding should be used in single phase motor.
There are many ways to reduce the noise, and the above points are for reference only.