Abstract: This paper aims at the breakage of the inducer and gear fracture of the speed-increasing box in the imported high-speed water injection pump of a high-pressure residue hydrogenation unit in China. The sequence of failures was determined based on the vibration, displacement, flow and current in the operation trend. Through spectrum analysis, the fault frequency of bearings and gears was eliminated, and the cause of the fault was finally confirmed to be gear fatigue. In order to solve the above problems, the gear was replaced. A 1∶1 mapping of the gear was conducted by a domestic machinery and equipment research institute after contact. Meanwhile, a technical agreement was signed to specify many important parameters such as gear surface grinding accuracy, surface quenching hardness, dynamic balance grade and so forth. And the manufacturing of the gear was completed and the operation test was carried out in the processing factory. Then on-site installation was completed. After the gear was replaced, the vibration and noise were in normal range during operation.

Key words: high-speed pump, gear, spectrum analysis, meshing frequency, side frequency, accuracy level