Abstract: In the no-load test of the 3^# motor in Tangshan compressor station of China–Russia Eastern Gas Pipeline Project before commissioning, the amplitude of exciter end rose rapidly and resulted in the shutdown when the operating speed reached 3 120 r/min.To solve this problem, the vibration analysis system was used to analyze the vibration spectrum of the exciter end.It was determined that the fault was caused by the high load upon the bearing bush at the exciter end, which further led to the high local load or local friction of the exciter rotor, induced the hot bending of rotor, caused the new unbalance, and further resulted in shutdown.Local friction marks was found during removal of the bearing bush, and the above analysis conclusion was verified.Through changing the height of bearing base at the exciter end, the bearing bush load was lowered and the rapid amplitude rise at the exciter end was eliminated.The exciter end was balanced and optimized by vector diagram method to ensure that the vibration at the exciter end can meet the requirements of brushless synchronous machines-500 kVA and larger(API 546-2008).Thereafter, the problem of high vibration at the exciter end of the 3^# motor in Tangshan compressor station has been quickly solved, and the safe operation can be ensured.