The Diagnosis And Analysis Of Starter’s Abnormal Noise

Starter is one of the important parts of auto starting system, noise produced by starteraffects customer evaluation to its overall performance. Study of starter abnormal noise andestablishment of the corresponding noise analysis model can not only realize the recognitionof the abnormal noise quickly, but also achieve the purpose of saving cost and time, so it isnecessary to study of starter abnormal noise. In this paper, the abnormal noise is analyzedfrom two aspects of theory and experiments. The main contents are as follows:Firstly, according to the starter’s working characteristics, using electromagnetic analysissoftware Ansoft was to analyze the temporal and spatial variation characteristics under fluxdensity, cogging torque, radial electromagnetic force with the speed of change. Then themodal and harmonic response characteristics were performed simulation by the cosimulationwith the help of finite element analysis software Workbench and noise analysis softwareLMS.Virtual.Lab. Since the electromagnetic force distribution in the value of the differencebetween the permanent magnet was large, the space-time distribution method was adopted toelectromagnetic force imposed on the permanent magnet at the harmonic response analysis.At the same time, the motor noise radiation cloud characteristics were researched and anlyzed.The experimental scheme of the noise and vibration was designed by the starter structureand noise characteristics, and then obtianed the starter’s frequency, sound pressure level,speed, vibration acceleration and other data. The elimination method was used to determinethe abnormal noise occurs in the motor. Because the range of speed changed widely afterpower-off of starter, the order analysis method which can distinguish effectively unstablesignal was used and the software Lms.Test.Lab was put received data into post-processing.Then, the combined with characteristics of the order and abnormal noise could determine theabnormal noise source.The study found that the main reason why abnormal noise generated after power-off ofstarter was resonance between electromagnetic noise frequency and the natural frequency.Considering the requirement of economy, performance index and structure of starter machine,I suggested that the starter natural frequency could be increased by changing the mechanismwhich enabled the starter resonance point located in the starter noise high region to cover theabnormal noise.