立式屏蔽电机半速涡动异常振动试验分析

针对某型主泵屏蔽电机在厂内试验中出现的异常振动问题进行了试验分析研究。首先,采用加速度计对屏蔽电机在变速过程中的振动进行了测试,获得了信号特征及其频谱成分;其次,采用锤击法对电机定子和转子的振动特性进行了模态测试,并利用小波对测试信号进行"去噪"处理,获得定、转子准确的频谱曲线。结果表明,半速涡动频率与定子系统固有频率耦合引发共振是造成电机振动异常的主要原因,多数情况下,这种耦合是发生在转子系统上。在此基础上,提出了增加试验临时支撑固定电机的假泵壳的质量,使定子系统固有频率降低,并调整轴承间隙来降低半速涡动的激振力幅值,起到了很好的消振效果。

Analysis of Abnormal Vibration of Half Speed Eddy for Vertical Canned Motor

The abnormal vibration problems of a certain type of main pump canned motor are investigated in a factory test based on experimental methods. First, the vibration of the vertical canned motor in a varying speed process is conduced with an accelerometer, and its signal characteristics and spectral components are obtained. Then, modal tests for the motor stator and rotor are performed using a hammering method. De-noising processing is conducted on the signals using wavelet, and accurate spectral curves are obtained. The results show that the frequency of the half speed eddy is coupled with the natural frequency of the stator system, while in most cases, this coupling occurs in the rotor system. Furthermore, in order to decrease the natural frequency of the stator system, a scheme of increasing the mass of the fake pump case, which is for the temporary supporting motor, is proposed. Meanwhile, the bearing clearance is adjusted to reduce the amplitude of the exciting force of the half speed eddy. These methods effectively mitigate vibration.