Reactive maintenance is the most dominant type of maintenance program in industry, and in this method, all converters and drives are allowed to run until they fail. Any replacement/ repair is performed after the failure occurs. This results in the highest downtime cost and may damage other components in the system. Other maintenance schemes attempt to predict the failure of any component and replace/repair the components before any failure takes place. A relative cost analysis for different pump maintenance schemes is shown in Fig. 1(b) [5]– [7], and the reliability-centered maintenance is the most effi- cient maintenance program, although it requires a sophisticated prognostics and diagnosis technique