This paper presents a detail research on a vibration high fault after overhaul occurred on a generator. During the overhaul, the generator rotor is returned to factory for processing and replaces section across the line of the generator excitation end. The gas turbine unit vibrates high in the idle 3000 r·min−1 and full load. The large vibration of the generator is mainly caused by the following two factors:the imbalance in the overhanging end of the generator rotor and the electrical fault in the generator itself. The unbalanced amount of generator overhang was successfully eliminated by dynamic balance test. The electrical fault of generator itself needs to be returned to the factory to handle.

The on-site vibration test and diagnostic analysis of the condensate pump motor vibration of a 390 MW gas turbine unit in a power plant were carried out. It is considered that the serious imbalance of the rotor of the condensate pump motor is the main cause of the vibration abnormality of the motor. The vibration anomaly is eliminated by the on-site dynamic balance test.

During the overhaul period of steam turbine in some plant, the blades’ vibrational security had been analyzed through the stationary frequency on the spot from the blades by using spectrum analyzer of Nanjing trued software engineering co., Ltd. The results of the test showed the turbine’s blades of next to last stages (stage groups) were safe when they were in operation with the working rotating speed.