A study of detection of broken rotor bars in induction motors using instantaneous power

Abstract

The paper demonstrates the practical implementation of the instantaneous power as diagnostic medium for condition monitoring. The analysis has been made on 2.2kW three-phase induction motors in a healthy and broken-rotor bars fault conditions at different loading conditions. It is well understood that stator current is widely used to detect the frequency sideband components for broken rotor bars. However, the practical results show the disability of stator current signal, in some cases, in detecting the sideband frequency components. Therefore, in this paper, the Fast Fourier Transform (FFT) of the instantaneous power has been used for detecting the broken rotor bar sidebands to achieve more accurate and reliable results. A modified sideband frequencies of the instantaneous power signals that reflects the condition of the motor were shown.