Review Different indexes for eccentricity faults diagnosis in three-phase squirrel-cage induction motors: A review Jawad Faiz * , Mansour Ojaghi Department of Electrical and Computer Engineering, University of Tehran, Tehran 1439957131, Iran article info Article history: Received 10 June 2007 Accepted 21 July 2008 Keywords: Induction motors Eccentricity fault Fault diagnosis techniques Indices abstract In this paper, a short introduction about different types of eccentricity faults in three-phase squirrel-cage induction motors is presented and their effects and consequences on the health and behavior of the motor are reviewed. Two fault diagnosis techniques are discussed, namely: invasive and non-invasive techniques. The relative advantages of the non-invasive techniques are also discussed. Various indices used in the non-invasive techniques are then briefly introduced and some outlines for continuing the research on every index are given. The advantages and disadvantages of the indices under different oper- ating conditions and for any type and eccentricity degree are then discussed together with some effective parameters of the motor. The results of this review are useful for manufacturers of fault diagnosis sys- tems in selecting proper indices for existing conditions and also for researchers in determining further research areas. Ó 2008 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................... 3 2. Eccentricity fault diagnosis techniques ...................................................................................... 4 3. Different indices used in non-invasive eccentricity fault diagnosis techniques ...................................................... 4 3.1. First index: normalized splitting severity factor ........................................................................ 4 3.2. Second index: difference of areas under Park’s current vector over two successive cycles to average of those areas ................. 5 3.3. Third index: high frequency components of stator current [1,9–14] ........................................................ 5 3.4. Fourth index: low frequency components of stator current [1,5,6,15–19] ................................................... 5 3.5. Fifth index: high and low frequency components of stator current [20–27] ................................................. 6 3.6. Sixth index: Gyration radius of developed torque ...................................................................... 6 3.7. Seventh index: low frequency components of spatial vector V qds and high frequency components of spatial vector I qds in synchronous reference frame [29,30]............................................................................................ 7 3.8. Eighth index: changing the zero sequence voltage when supplying motor with special pulses by inverter [31] .................... 8 3.9. Ninth index: ratio of sum of the stator current low frequency components and motor no-load current [32] ....................... 8 3.10. Tenth index: summation of low frequency component of spatial vector of current and voltage of stator [33] ...................... 9 3.11. Eleventh index: amplitude of negative sequence component of fundamental frequency of stator current [34] ..................... 9 3.12. Twelfth index: the frequency components of instantaneous power [36–38] ................................................ 10 4. Analysis of advantages and disadvantages of the indexes ...................................................................... 10 5. Conclusions ........................................................................................................... 12 Acknowledgement ..................................................................................................... 12 References ........................................................................................................... 12 0957-4158/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.mechatronics.2008.07.004 * Corresponding author. Tel.: +98 21 88003330; fax: +98 21 88633029. E-mail address: jfaiz@ut.ac.ir (J. Faiz). Mechatronics 19 (2009) 2–13 Contents lists available at ScienceDirect Mechatronics journal homepage: www.elsevier.com/locate/mechatronics