Analysis of noise and noise reduction measures generated by motors
4, mechanical noise
Rotating motor noise is mainly mechanical noise, and large, high-speed motors are prone to such noise.
Poor rotor dynamic balance is one of the most common causes of mechanical and mechanical noise. Increasing the rotor dynamic balance accuracy can effectively reduce this noise. Poor installation and adjustment, mechanical noise will also occur when the natural frequency and the rotational frequency of the rotor components are the same. When the motor is equipped with an end shield type hood, the cover is often shaken by the vibration of the motor, vibrates, and noise is generated. In this case, the vibration of the stator of the motor is often the excitation source of the end cover or the hood. To reduce the vibration noise, the measure is to increase the dynamic rigidity of the end cover and the cover. A vibration absorbing material such as felt is added to the joint between the end cover and the stator to reduce the vibration amplitude of the stator.
5, load noise
The main causes of such noise are manufacturing defects, assembly gaps, and damage to the working surface and electrical corrosion during operation, transportation, and installation, which can cause unbalanced bearing operation and irregular impact. For example, the surface roughness of the shaft is not up to standard, the roundness of the bearing hole is out of tolerance (stator or end cap), the material of the bearing hole is poor, and the armature mandrel is slightly scratched. Noise reduction measures include: When testing the bearing process and entering the factory, it is necessary to strengthen the test of the smoothness, roundness and surface roughness of the inner wall of the bearing; confirm whether the oil hole or material of the inner wall of the bearing meets the requirements, and whether the roundness of the bearing hole exceeds Poor; check the shaft head carefully to confirm whether the end cap side shaft is qualified; when the string shaft is riveted, whether the shaft end is scratched.
In short, in order to effectively control and reduce motor noise pollution, in addition to good quality in the production process, we must also be proficient in monitoring, diagnosing and identifying the motor noise in order to take effective measures to reduce noise.
