大型立式电动机特定边界条件下的振动特性仿真与实验研究

Simulation and experiment for vibration characteristics of large-type vertical motor

考虑大型立式电动机的承载结构特点和机电耦合、电磁耦合作用,应用虚拟样机技术和有限元仿真软件,建立了某大型立式电动机的有限元模型,分析了电机振动变形和结构破坏的分布规律,确定了大型电动机结构变形与破坏的主要形式和部位。研究结果表明,单边磁拉力的不平衡作用是引起大型电机振动的重要激振源,当主波磁场产生的单边磁拉力的频率与电机某阶固有频率接近或者相同时,可能引起相关结构或者整机的强烈振动。同时,地脚螺栓的联接刚度对电机固有频率有较大影响,随着地脚螺栓数量的增加,电机的固有频率随之提高;当地脚螺栓失效时,会使得电机的固有频率降低,从而可能更加容易引起电机生产剧烈振动或者共振。

The finite element model of a large-type vertical motor was established based on virtual prototype and finite element simulation techniques,in which bearing characteristics of the motor structure and effects of electromechanical coupling & electromagnetism coupling were considered.The distribution rules of motor vibration distortion and structure destroy were analyzed,and the main destroy form and location of the motor structure were confirmed according to the finite element analyses.The results show that unalance effect of unilateral magnetic force is an important vibration source.The correlated structures or the whole motor could be caused to vibrate intensively while the frequency of the unilateral magnetic force produced by the main magnetic field is close to some natural frequency of the motor.The joint stiffness of foot bolts affects the natural frequencies of the motor clearly.With the increase of foot bolts number,the natural frequencies of large-type motor will increase;while foot bolts become invalid,the natural frequencies will decrcase,and this could cause the motor to vibrate tempestuously or resonate.