Broken-Rotor-Bar Detection Through STFT and Windowing Functions

Abstract

Monitoring systems for induction motor fault detection have been of great interest for industry in recent years. Those based on the analysis of the electric current supply are the most common; since the current signal provides relevant information regarding the motor condition. The Fourier transform is a popular method for performing this analysis; however, it does not allow seeing the evolution of the signal through time. On the other hand, the Short-Time Fourier Transform (STFT) has proven to be useful for analyzing the signal-frequency evolution through time; unfortunately, its timefrequency representation heavily depends on the used-window size, compromising its resolution. In this work, a method based on window functions and STFT is proposed for enhancing the resolution of the time-frequency representation. The proposed approach is applied on the electric current signal supplied to an induction motor, improving the visualization of characteristicfrequency components of broken rotor bars.