Predictive versus preventive maintenance

This paper presents electrical equipment maintenance by condition-based maintenance (CBM). In the CBM approach, equipment maintenance based on a routine schedule can be replaced with an approach based on system wellness diagnostics. This approach might rely on noninvasive monitoring of three-phase induction motors to report equipment condition and enable maintenance intervention before a failure occurs. Pump cavitation, rotational unbalance and mechanical alignment are some of the areas where a mathematical model has been developed using fast Fourier transform (FFT) analysis, enabling online diagnostics during operation. Also discusses mathematical model and field tests to validate the model and introduce a motor-wellness relay that could be used to perform online diagnostics. Alternative system communication architecture to support a wellness platform are also reviewed and discussed.