Abstract: The electromagnetic noise generated by AC asynchronous motor will seriously affect the user experience, need to focus on the solution. First of all, through the listening method, frequency spectrum analysis method, the suddenly loses power, audio function analysis of the fault prototype of the two high and one low abnormal noise diagnosis, identify the different sounds for the electromagnetic different sound of 1033 Hz and 400 Hz. Then, through mechanism analysis and theoretical frequency calculation, the noise caused by the harmonic interaction between stator and rotor teeth and the noise caused by the interaction between fundamental magnetic field and power supply harmonics are determined. According to the noise types, the solutions of optimizing the ratio of stator and rotor slots and the i-shaped rubber pad are proposed respectively. Finally, through spectrum analysis and listening test, it is proved that the solution is effective.

Key words: Rang hood, Asynchronous motor, Electromagnetic noise, Slot coordination, I-shaped cushion