The measurement and indexing of unbalanced magnetic pull in electrical machines

Unbalanced magnetic pull in cylindrical electrical machines has been studied by several authors but it can be hard to quantify and measure. This paper reviews some of the work related to UMP calculation and measurement and develops the concept of a UMP index in order to allow comparative studies. This is because the UMP can vary greatly in terms of magnitude depending on the type and topology of the machine and also the loading. Methods for measurement of UMP are also discussed and results put forward from a UMP measurement rig.

[1]  H. Toliyat,et al.  Effect of Magnetic Saturation on Static and Mixed Eccentricity Fault Diagnosis in Induction Motor , 2009, IEEE Transactions on Magnetics.

[2]  D. Dorrell.  Calculation of Unbalanced Magnetic Pull in Cage Induction Machines , 1993 .

[3]  H.A. Toliyat,et al.  Modeling and analysis of cage induction motors under rotor misalignment and air gap eccentricity , 2005, Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005..

[4]  Z.J. Liu,et al.  Effect of Radial Magnetic Forces in Permanent Magnet Motors With Rotor Eccentricity , 2007, IEEE Transactions on Magnetics.

[5]  M. Hsieh,et al.  Unbalanced Magnet Pull in Large Brushless Rare-Earth Permanent Magnet Motors With Rotor Eccentricity , 2009, IEEE Transactions on Magnetics.

[6]  Willy Geysen,et al.  Influence of rotor-bar stiffness on the critical speed of an induction motor with an aluminium squirrel cage , 1984 .

[7]  D. G. Dorrell,et al.  Influence of Parallel Paths on Current-Regulated Sine-Wave Interior-Permanent-Magnet Machines With Rotor Eccentricity , 2012, IEEE Transactions on Industry Applications.

[8]  A. Arkkio,et al.  Electromagnetic force on a whirling cage rotor , 2000 .

[9]  D. G. Dorrell,et al.  Calculation and measurement of unbalanced magnetic pull in cage induction motors with eccentric rotors. I. Analytical model , 1996 .

[10]  Iqbal Husain,et al.  Unbalanced force calculation in switched-reluctance machines , 2000 .

[11]  J. F. Eastham,et al.  Transient unbalanced magnetic pull in change-pole induction motors , 1989 .

[12]  Z.Q. Zhu,et al.  Unbalanced Magnetic Forces in Permanent-Magnet Brushless Machines With Diametrically Asymmetric Phase Windings , 2005, IEEE Transactions on Industry Applications.

[13]  G. R. Bindu,et al.  Unbalanced Magnetic Pull in Train-Lighting Brushless Alternators With Static Eccentricity , 2008, IEEE Transactions on Vehicular Technology.

[14]  David G. Dorrell,et al.  Calculation and measurement of unbalanced magnetic pull in cage induction motors with eccentric rotors. Part 2: Experimental investigation , 1996 .

[15]  A. Arkkio,et al.  Comparison of the Unbalanced Magnetic Pull Mitigation by the Parallel Paths in the Stator and Rotor Windings , 2007, IEEE Transactions on Magnetics.

[16]  C. Cossar,et al.  Effects of rotor eccentricity on torque in switched reluctance Machines , 2005, IEEE Transactions on Magnetics.

[17]  R. Krishnan,et al.  Noise in electric machines: a review , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[18]  David G. Dorrell,et al.  Magnetic Bearings and Bearingless Drives , 2005 .

[19]  L. Wang,et al.  Finite-Element Analysis of Unbalanced Magnetic Pull in a Large Hydro-Generator Under Practical Operations , 2008, IEEE Transactions on Magnetics.

[20]  M. Leijon,et al.  Saturation Effects on Unbalanced Magnetic Pull in a Hydroelectric Generator With an Eccentric Rotor , 2007, IEEE Transactions on Magnetics.

[21]  David G. Dorrell.  Experimental behaviour of unbalanced magnetic pull in 3-phase induction motors with eccentric rotors and the relationship with tooth saturation , 1999 .

[22]  David G. Dorrell,et al.  Measurement and Calculation of Unbalanced Magnetic Pull in Wound Rotor Induction Machine , 2014, IEEE Transactions on Magnetics.

[23]  David G. Dorrell.  Calculation of unbalanced magnetic pull in small cage induction motors with skewed rotors and dynamic rotor eccentricity , 1996 .

[24]  David G. Dorrell,et al.  Analysis of airgap flux, current and vibration signals as a function of the combination of static and dynamic airgap eccentricity in 3-phase induction motors , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[25]  Mircea Popescu,et al.  Unbalanced Magnetic Pull Due to Asymmetry and Low-Level Static Rotor Eccentricity in Fractional-Slot Brushless Permanent-Magnet Motors With Surface-Magnet and Consequent-Pole Rotors , 2010, IEEE Transactions on Magnetics.

[26]  D G Dorrell,et al.  Sources and Characteristics of Unbalanced Magnetic Pull in Three-Phase Cage Induction Motors With Axial-Varying Rotor Eccentricity , 2011, IEEE Transactions on Industry Applications.

[27]  M. Ooshima,et al.  Development of a Four-Axis Actively Controlled Consequent-Pole-Type Bearingless Motor , 2009, IEEE Transactions on Industry Applications.