中文摘要：

针对某200MW空冷机组新机启动及运行过程中,存在2号轴承轴振在2 835~2 865r/min出现的振动响应峰值、启动及带负荷过程1-3号轴振爬升,以及定速3 000r/min后3-5号轴承轴振偏大等问题,依据振动特征并结合现场经验进行了分析。结果表明：其振动主要原因为2号轴承轴振传感器支架结构共振、汽缸膨胀不畅、轴系质量不平衡。通过实施现场支架加固、高中压缸滑销系统修配、轴系动平衡等措施后,机组轴系振动处于优良水平。

英文摘要：

During start up and operation process of a newly built air cooling 200 MW turbo-generator,serious vibration faults occurred,such as No.2bearing shaft vibration peak with turbine speed ranging from 2835r/min to 2 865r/min,No.1to No.3 shaft bearing vibration climbing,and No.3to No.5shaft bearing vibration exceeded the standard.In order to solve this problem,the vibration data in site were measured and the record of operation and examination was analyzed.It can be found that the fault was caused by the sensor bracket resonance,poor expansion of the cylinder and the rotor quality imbalance.Through bracket reinforcement,sliding key system repairing and high-speed dynamic balance,the vibration of the unit shaft system can be controlled at a level of excellence.