New Method for Spectral Leakage Reduction in the FFT of Stator Currents: Application to the Diagnosis of Bar Breakages in Cage Motors Working at Very Low Slip

Motor current signature analysis has become a widespread fault diagnosis technique for induction machines (IMs), because it is noninvasive and requires low resources of hardware (a sensor) software fast Fourier transform). Nevertheless, its industrial application faces practical problems. One most challenging scenarios the detection broken bars in IMs working at very slip, like large with small rated or unloaded motors off-line tests. In these cases, leakage main supply component can hide harmonics, even severe fault. Diverse solutions to this problem have been proposed, such as use smoothing windows, advanced spectral estimators, removal component. methods modify content signal add high computational burden. work, new approach based on fine spectrum, obtained via simple zero padding, followed by extraction practically leakage-free conventional, coarse spectrum. The method experimentally validated bar 3.15-MW motor.