What is the main reason for the noise when the motor is running?

Update:13 Apr 2020
Summary:

When the motor is running, there are three aspects of n […]

When the motor is running, there are three aspects of noise, one is electromagnetic noise, the other is mechanical noise, and the third is ventilation noise.

1.Electromagnetic noise. Mainly caused by the air gap harmonic magnetic field, the radial alternating magnetic tensile force generated by the harmonic flux interaction of the stator rotor teeth will cause periodic dynamic radial deformation of the stator core yoke, which will stimulate the stator to generate electromagnetic noise. In addition, broken bars of squirrel-cage rotors, short-circuit between winding rotor turns, rotor eccentricity, asymmetry of stator windings or short-circuit between turns, etc., can cause electromagnetic noise.

2.Mechanical noise. It is mainly bearing noise and structural component resonance noise, followed by rotational vibration noise.

3.Ventilation noise. The main reason is the noise generated by the protruding parts such as fan blades and rotor blades impacting the air periodically when the motor rotates.

The main reason for the noise of Liming motor running, there is noise or scream:

  1. Uneven rotor gap
  2. The quality of the bearing is not good, the grease is too little, the bearing is worn, the bearing is not cleaned cleanly, and the lubricant has impurities
  3. Scrape insulating paper or slot wedge
  4. Loose rotor core
  5. Three-phase voltage is seriously unbalanced
  6. Motor overloaded
  7. A foreign object screams out of the air duct
  8. The power supply voltage is too high
  9. Inter-phase short circuit or grounding between winding turns
  10. Constant rotor friction
  11. Unreasonable distribution of motor windings
  12. Loose fan and shaft of motor shaft and rotor core
  13. Stator wiring error
  14. Excessive fan burr produces scream
  15. Stator turns per phase are not equal
  16. Motor installation is not concentric with equipment
  17. Loose foot screws during motor installation

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