The investigation of motor current signals from a centrifugal pump for fault diagnosis

In this paper, motor current signals from electrical control systems, rather than installing additional measurement systems, are characterised for the fault diagnosis of centrifugal pumps. Modulation signal bispectrum (MSB) analysis is applied to reveal the weak nonlinear characteristics of current signals when the pump with different impeller faults operates under a wide range of flow conditions. Experimental results show that two static features including the amplitude at supply frequency and the frequency value of bar-passing frequency can be based on to diagnose impeller defects on exit vane tips and inlet vane tips. In addition, the dynamic parameter of sidebands at vane-passing frequency can also be a good indicator for differentiating between the faults.