LI Bin
（Ningbo Fotile Kitchen Ware Co.，Ltd.，Ningbo 315336，China）
Abstract：Aiming at the abnormal electromagnetic noise and vibration occurred when the motor of the range hood's fan operated，whichcaused by interaction of the harmonic voltage in power grid and magnetic field of the motor，a technical approach about the vibrationenergy absorption system optimization design was presented to eliminate the abnormal noise and vibration. The radiation noise frequencyspectrum analysis and power harmonic characteristic were adopted to analyze the mechanism of noise and vibration. Through the test，the
most obvious characteristic line spectrum frequency was found. Different damping pad structure between the motor and volute wereevaluated，and the best structure scheme was produced. The experimental results show that the new motor damping pad with micro-elasticunits array could reduce the line spectrum of 200 Hz effectively，the sound quality and the whole machine vibration problem is improvedsignificantly.
Key words：range hood；sound quality；abnormal sound；optimal design