A Fault Diagnosis Approach for Broken Rotor Bars Based on EMD and Envelope Analysis

• Published in: Journal of China University of Mining and Technology Vol. 17; no. 2; pp. 205 - 209
• Main Authors: ZHANG, Jian-wen, ZHU, Ning-hui, YANG, Li, YAO, Qi, LU, Qing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2007; School of Information & Electrical Engineering, China University of Mining & Technology, Xuzhou, Jiangsu 221008, China
• Subjects: analysis of envelope; EMD; fault of broken rotor bar; TM 343.3; fault of broken rotor bar; analysis of envelope; TM 343.3; EMD
• ISSN: 1006-1266
• DOI: 10.1016/S1006-1266(07)60073-X

Empirical Mode Decomposition (EMD) used to deal with non-linear and non-stable signals, is a time-frequency analytical method that has been developed recently. In this paper the EMD method is used to filter the noise from the stator current signal that arises when rotor bars break. Then a Hilbert Transform is used to extract the envelope from the filtered signal. With the EMD method again, the frequency band containing the fault characteristic-frequency components, 2 sf, can be extracted from the signal's envelope. The last step is to use a Fast Fourier Transform (FFT) method to extract the fault characteristic frequency. This frequency can be detected in actual data from a faulty motor, as shown by example. Compared to the Extend Park Vector method this method is proved to be more sensitive under light motor load.