Distinguishing Load Torque Oscillations and Eccentricity Faults in Induction Motors Using Stator Current Wigner Distributions

• Published in: IEEE transactions on industry applications Vol. 45; no. 6; pp. 1991 - 2000
• Main Authors: Blodt, M., Regnier, J., Faucher, J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2009; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplitude modulation; Condition monitoring; Diagnosis; Eccentricity; Fault detection; Fault diagnosis; Faults; Frequency; induction motor drives; Induction motors; load unbalance; motor current signature analysis; Oscillations; Phase modulation; Rotors; Shafts; Signatures; Stators; Torque; torque oscillation; Wigner distribution; Wigner Distribution (WD)
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2009.2031888

This paper proposes a novel diagnosis method for detection and discrimination of two typical mechanical failures in induction motors by stator current analysis: load torque oscillations and dynamic rotor eccentricity. A theoretical analysis shows that each fault modulates the stator current in a different way: torque oscillations lead to stator current phase modulation, whereas rotor eccentricities produce stator current amplitude modulation. The use of traditional current spectrum analysis involves identical frequency signatures with the two fault types. A time-frequency analysis of the stator current with the Wigner distribution leads to different fault signatures that can be used for a more accurate diagnosis. The theoretical considerations and the proposed diagnosis techniques are validated on experimental signals.