Abstract: A hydrogen compressor, the key equipment of a petrochemical plant, started after overhaul. It shut down by vibration interlock at 600 revolutions per minute. Through spectrum analysis, it was considered that there was serious rub-impact fault between the dynamic and static parts of the compressor. The main cause of the fault was the wrong size of the half-wheel of the locomotive motor. A repair plan to rework the conductive contacts is carried out and then the compressor returned to normal operation. This paper expounds the mechanism vibration exceeding the allowable norm caused by rub-impact of dynamic and static parts of the compressor. It introduces an effective method for diagnosis of such failure through analyzing a rub-impact fault between the dynamic and static parts of a compressor. This method can accurately determine such faults and draw diagnostic conclusions, which is helpful for on-site maintenance guiding.

Key words: centrifugal compressor, rub-impact fault, mechanism; spectrum analysis, case analysis