Abstract: The bearing-pad vibration and shaft vibration of a 600-MW hydrogen-cooled generator rotor of a power plant have been keeping on intensifying with increasing unit loading since its operation. Through the tests of the active power variation, rotor current variation and hydrogen temperature variation, the main cause of the vibration is figured out that new mass imbalance is generated by heat distortion at the end component of the generator rotor due to the poor manufacturing process. Consequently, the third-order vibration occurs, which causes the vibration to become severer. The amplitude and phase of the heat distortion are calculated and in consideration of the vibration balance under the cold and hot states, the vibration of the generator rotor is harnessed effectively by adding weights at the end of the generator rotor.

Key words: generator, unstable vibration, analysis, control