Complementary diagnosis of rotor asymmetries through the tracing of the Right Sideband Component in the stator startup current

In this paper, the tracing of the right sideband component (RSC) evolution in the stator startup current is proposed for the diagnosis of rotor asymmetries in induction machines. Although several works have dealt with the detection of the left sideband component (LSC) during the transient, few contributions have focused on the RSC, perhaps due to its more difficult detection, since it has often lower amplitude. In this work, several signal processing techniques, such as the short time Fourier transform (STFT), the discrete wavelet transform (DWT), the continuous wavelet transform (CWT) and band pass filtering are applied in order to extract this component during the transient. Several experimental startup current signals are used for this purpose. The results show that the transient extraction of the RSC might constitute an additional source of information which could enable a more reliable diagnosis of the fault, mainly in those cases in which the transient LSC evolution could be partially masked by other phenomena.