汽轮发电机轴振和轴承座振动非同步变化现象和分析

建立了转子-轴承系统动力学模型,分析启停机过程中轴振和轴承座振动随转速变化规律。研究结果表明,升速过程中不同转速区间内轴振和轴承座振动随转速变化趋势并不完全同步。转速较低和较高时,轴振和轴承座振动随转速变化基本同步,但在一定转速区间内有可能出现轴振和轴承座振动反向变化现象。当轴承座-支撑系统固有频率点位于工作频率点附近时,会出现动力吸振现象,转子振动转移到轴承座上,导致机组出现大幅轴承座振动。针对2台发电机组上发生的振动故障进行了分析,应用研究结果解释了轴承座异常振动现象,通过动平衡试验解决了机组振动故障。

Analysis on the Unsynchronous Change Phenomenon and Its Reason of Shaft Vibrationand Bearing Vibration of Turbine Generator Unit

The dynamic model of rotor-bearing system was established to analyze the variation rules of shaft vibration and bearing vibration during the starting and stopping process.The results show that the variation trend of shaft vibration and bearing vibration with rotation speed is not completely synchronized in the total speed-up process.When the rotating speed is low or high,the shaft vibration and the bearing vibration are synchronous with rotating speed.When the rotating speed is in a certain range,it is possible to see the reverse variation of the shaft vibration and the bearing vibration.When the natural frequency of the bearing-support system is near the working frequency,dynamic absorption phenomenon occurs.The vibration of the rotor transfers to the bearing,resulting in large structural vibration.The vibration faults of two units were analyzed.The abnormal vibration phenomena of bearing were explained by the results of this paper,and the vibration faults were solved by in field rotor balance.