Vibration Based Diagnosis of a Centrifugal Pump

The centrifugal pump has a long history of frequent failure of anti-friction bearing since its commissioning in 1985. Vibration based conventional condition monitoring has regularly been used to identify the progressive nature of the bearing failure, but has failed to identify the root cause. Modal tests have been conducted on the pump assembly to understand the dynamics of the complete assembly. A typical case of the resonance of the bearing pedestals with 2X component (two times the pump RPM) of the response during pump operation mainly due to nonlinear interaction between the pump foundation and the concrete floor has been identified as the main source of the bearing failure. The results, observations, and the diagnosis to identify the root cause are discussed here.