Y Series Three Phase Asynchronous Motor Vibration Analysis And Suppression

The motor vibration problem stands more and more out with the wide application of Y-series- Asynchronous Motor in national economy. This vibration leads to serious harm to industrial production, that is, to reduce the motor efficiency, to accelerate the bearing wear and tear, to affect its ancillary equipment, to pollute the working environment with the vibrating noise, and to lower the insulating property of stator winding. Therefore, there are specifically broad engineering background and application value to analyze the vibration of Y-series motor.Combining the theoretical analysis with on-site tests, the writer makes a deep analysis on all the factors that might cause the vibration of Y-series- motors both electro-magnetically and mechanically, fully summarizes the causes to the rotor unbalance, and the way to improve the quality of the rotor core and winding so as to lower the vibration.The key measure of the reduction of motor vibration is to improve rotor balance accuracy. The writer summarizes the questions that shall pay attention to when measuring the rotor dynamic balance; takes special guarantee measures for different types of rotors, and gives the way to improve the accuracy of rotor dynamic balance in structure design, manufacturing processes and balance operation, etc..In daily production, the writer has made a lot of favorable tests to improve the quality of manufacturing processes of Y-series motors so as to lower motor vibration. Inappropriate choice of bearing fitting allowance is the main reason for above-norm vibration of motors. The way of changing the bearing chamber from the former Js6 to H7 basically relieve the vibration caused by the tight radial clearance due to the bearing heat expansion. The motor vibration can be efficiently reduced by the reasonable controls of the motor axial clearance and reduction of the axial movement of rotor. Through analysis and trials, the writer changes the motor frame rabbet length and size tolerance of the rotor bearing end distance from h11 to h10 without more difficulties in machining. But the bearing can come into proper working conditions. It proves that the vibration went down greatly on the verification motor. In China motor industry, the post-positioning of stator core is firstly applied to large and medium-sized high voltage motors in our factory. This solution has efficiently relieved the possible axial additional magnetic tension on stator and rotor, and ensures the proper positioning of rotor in bearing, especially the sliding bearing, preventing the collision with the bearing. Some efficient trials are also made on the control of the tolerances on the key parts, the quality of stator/rotor core stacking and rolling bearing assembly.Finally, the writer introduces the application of frequency-spectrum analysis into the vibration diagnosis of motors. A good result has been achieved to solve the motor vibration with the comprehensive application of the vibration signals / stator current signal frequency spectrum.