汽轮发电机3号轴承振动大分析及处理

Analysis and Treatment on the Large Amplitude Vibration of No.3 Bearing in a Turbine Generator

某25 MW汽轮发电机3号轴承振动大,经过几次检修,振动异常问题始终未能解决,导致汽轮发电机组停机。对汽轮发电机运行参数、振动图谱、轴承结构、检修过程进行分析,确定了振动大的主要原因为轴承底部垫块虚接导致支撑系统松动,发电机转子下沉与轴封、油挡发生摩擦,对中发生改变。通过优化转子对中调整工艺和调整轴承装配间隙,3号轴承振动幅值明显下降,机组能够安全稳定运行。合理的转子检修装配方法对汽轮发电机的可靠运行至关重要。

For the No.3 bearing with large amplitude vibration in a 25 MW turbine generator, the problem of abnormal vibration was not be solved after maintaining in several times, which resulted in the shutdown of the turbo-generator set. Through analyses on the operation parameter, vibration spectrum, bearing structure and maintenance process of the turbine generator, it is confirmed that the main reason of large amplitude vibration is the change of centering, which is caused by the friction between the sinking generator rotor and the shaft seal and oil shield with the loosening of support system due to the false connection of the supporting bracket at bearing bottom. By means of optimizing the centering adjustment process for rotor and adjusting the assembling clearance for bearing, the vibration amplitude of No.3 bearing is reduced significantly, which can guarantee the safety and stability of the unit operation. The reasonable maintaining and assembling method for rotor is vitally important for the reliable operation of turbine generator.