“…Different condition based maintenance systems (CBMS) for IMs have been described in the technical literature [8], based on vibrations [9], sound analysis [10,11], thermal signals [12], etc. Among them, motor current signature analysis (MCSA) [13,14,15,16] has gained an increasing interest, because it can operate on-line, detecting different and possibly simultaneous types of fault, and can be implemented using non-invasive [17] low-cost current sensors, and fast processing algorithms, especially the fast Fourier transform (FFT). MCSA is based on the detection of a set of harmonic components generated by each type fault, whose frequencies constitute a unique fault signature [18].…”