A Normalized Frequency-Domain Energy Operator for Broken Rotor Bar Fault Diagnosis

Abstract

In the motor current signal, the characteristic frequency of broken rotor bar (BRB) fault is modulated by the supply frequency and it decreases with the decrease of the load, resulting it to be easily buried under light load conditions. Teager-Kaiser energy operator (TKEO) has shown better performance to detect BRB faults than classical methods, such as envelope and spectral analysis. However, the original definition of TKEO leads to its result lack of physical meanings and the causal processing in TKEO can lead to phase distortion and non-ideal filter characteristics. Therefore, this paper proposes a normalized frequency domain energy operator (FDEO) for the BRB fault diagnosis, which does not require causal processing and calculates multiple differentiations in the frequency domain with equal accuracy in one operation. Furthermore, normalized FDEO removes the influence of the supply frequency followed by spectral analysis to extract fault features. The mathematical model of induction motor under healthy and faulty condition are studied in this article. Then, the proposed approach is experimentally validated with seeded one and two BRB faults operating under various load conditions. To verify the effectiveness, the results are compared with TKEO, envelope and spectral analysis. It was found that the proposed method provides slightly obvious fault features with respect to TKEO, especially when the IMs run under light load conditions with two BRB faults. Index Terms-Broken rotor bar, Induction motor, Motor current signature analysis, Frequency domain energy operator， Fault diagnosis. NOMENCLATURE () instantaneous amplitude the amplitude of the fault frequency for fault case the amplitude of the fault frequency for normal case the modulation index Envsq[ ()] the squared envelope of () ℱ Fourier transform ℱ −1 inverse Fourier transform BRB fault characteristic frequency supply frequency rotating frequency the amplitude of the supply current

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“…Failures of IMs can be originated from faults in the stator, the rotor, the motor mechanical system including bearing and shaft, or external sources [2,3]. Many surveys were conducted to estimate the percentage of failures related to each motor component.…”

“…In addition, the backward magnetic field increases due to rotor circuit asymmetry which is reflected in the stator current harmonic content and other motor quantities [10]. Thus, the BBF reduces motor efficiency and reliability [3]. Also, the BBF causes the vibration of the shaft that may lead to bearing and rotor eccentricity faults [11].…”

Overtemperature fault diagnosis of front bearing for main spindle based on CNN + LSTM

“…To establish a fault diagnosis model, traditional methods have many ways such as: frequency domain analysis method [9]. Zhang used wavelet transform to diagnose the faults of the circuit components of the wind turbine inverter, wavelet transformed the collected voltage signal, decomposed and reconstructed the original signal for fault diagnosis and achieved good results [10].…”

A Novel Method for Diagnosis of Broken Bars Based on Optimum Resolution of Prescient Direction Algorithm

“…Among the various faults, broken rotor bars (BRBs) account for about 10% of total failures. Induction motor faults such as BRBs can result in potential physical damage to motor itself as well as to the reliability and safety of industrial operations, and also increase the operational costs [1][2][3]. Therefore, induction motor condition monitoring and fault diagnostics have created substantial interest among researchers in the last decades, and many of them are with great respect to BRB detection.…”