An improved model of induction motors for diagnosis purposes – Slot skewing effect and air–gap eccentricity faults

• Published in: Energy conversion and management Vol. 50; no. 5; pp. 1336 - 1347
• Main Authors: Ghoggal, A., Zouzou, S.E., Razik, H., Sahraoui, M., Khezzar, A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2009; Elsevier
• Subjects: A.c. Machines; Applied sciences; Axial air–gap eccentricity; Diagnostic; Electrical engineering. Electrical power engineering; Electrical machines; Engineering Sciences; Exact sciences and technology; Induction motor; Miscellaneous; MWFA; Other; Skew; Space harmonics; Induction motor; Axial air–gap eccentricity; MWFA; Diagnostic; Skew; Space harmonics; Performance evaluation; Gap function; Asynchronous motor; Experimental study; Fourier series; Inductance; Ac motor; Axial air-gap eccentricity; Analytical method; Air gap; System simulation; Electric motor; Diagnostic aid; Effectiveness factor; Mathematical model; Machine windings
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2009.01.003

This paper describes an improved method for the modeling of axial and radial eccentricities in induction motors (IM). The model is based on an extension of the modified winding function approach (MWFA) which allows for all harmonics of the magnetomotive force (MMF) to be taken into account. It is shown that a plane view of IM gets easily the motor inductances and reduces considerably the calculation process. The described technique includes accurately the slot skewing effect and leads to pure analytical expressions of the inductances in case of radial eccentricity. In order to model the static, dynamic or mixed axial eccentricity, three suitable alternatives are explained. Unlike the previous proposals, the discussed alternatives take into account all the harmonics of the inverse of air–gap function without any development in Fourier series. Simulation results as well as experimental verifications prove the usefulness and the effectiveness of the proposed model.