Abstract: The paper established a finite element mod-eling of a 1000 MW unit.The model was used to study the vibration response characteristics of the shafts at both ends of the generator.The simulation results showed that the first-order imbalance of the generator first caused the in-phase vibration at the first-order critical speed of the generator when the two ends of the generator support simi-lar characteristics.When the difference in support character-istics between the two ends of the generator was large, the first-order unbalance of the generator provoked a large inphase vibration at the first-order critical speed of the gener-ator, and also provoked a large reverse component.Finally, the reliability of the conclusion was verified by combining the abnormal vibration diagnosis and processing cases of a generator.

Key words: turbo-generator, supporting characteristic, vibration