Effects of rotor eccentricity and parallel windings on induction machine behavior: a study using finite element analysis

DeBortoli, M.J.; Salon, S.J.; Burow, D.W.; Slavik, C.J.

doi:10.1109/20.250728

Cited by 101 publications

(54 citation statements)

References 3 publications

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“…To model electrical machines under different types of faults, winding function approach (WFA) [1] and finite element method (FEM) [2] have been introduced as appropriate modeling methods. Although FEM provides precise modeling, its application is complicated and time consuming especially for the analysis of electrical machines with asymmetry in the motor body such as eccentricity [2,3].…”

Section: Introductionmentioning

confidence: 99%

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An Improved Analytical Model for Salient Pole Synchronous Machines Under General Eccentricity Fault

Akbari¹

2013

PIER B

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Abstract-This paper develops a more precise analytical model for calculating salient pole synchronous machine (SPSM) inductances in case of general eccentricity including static, dynamic and mixed eccentricities. The developed method is based on the modified winding function approach (MWFA) which accurately considers variable air gap function and leads to pure analytical expressions of inductances. Available analytical techniques, based on MWFA, approximate the air gap function and simplify the geometrical model of SPSM, whereas, in this study, the influence of the openings between the rotor salient poles has been taken into account by using an effective form of rotor pole shoes. Using this technique, flux fringing effect is considered. By taking into account machine geometry, type of windings connection and flux fringing effect, this method is able to model most of the important features of an eccentric SPSM. The developed analytical expressions can calculate time varying inductances of SPSMs with any eccentricity type and degree in the frame of a single program. Simulation results for static eccentricity are compared with experimental tests on a laboratory generator to verify accuracy of the proposed model.

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Section: Introductionmentioning

confidence: 99%

“…Although FEM provides precise modeling, its application is complicated and time consuming especially for the analysis of electrical machines with asymmetry in the motor body such as eccentricity [2,3].…”

Section: Introductionmentioning

confidence: 99%

An Improved Analytical Model for Salient Pole Synchronous Machines Under General Eccentricity Fault

Akbari¹

2013

PIER B

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“…His research subject was a synchronous turbo-generator. Over a decade later, Salon et al (1992), DeBortoli et al (1993), Arkkio & Lindgren (1994), Arkkio (1996) extended the application area to induction motors, equalising currents and parallel circuits of the stator windings. Stoll (1997) developed a simple computational model to predict the UMP caused by static eccentricity.…”

Section: Rotordynamic Instabilitymentioning

confidence: 99%

Electromechanical interaction in rotordynamics of cage induction motors

Holopainen

Tenhunen

Arkkio

2005

Journal of Sound and Vibration

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Electromagnetic fields in the air gap of an electric machine produce electromagnetic forces between the rotor and stator. The total force exerted on the rotor due to the eccentric rotor position is called the unbalanced magnetic pull. This eccentricity force is directed roughly over the shortest air gap. At low frequencies, the vibration amplitudes of flexural modes may be large enough to couple the electromagnetic system to the mechanical one. This electromechanical interaction changes the vibration behaviour of the system.The main purpose of this dissertation is to reveal the main rotordynamic consequences induced by the electromechanical interaction in cage induction motors. Another goal is to achieve this by deriving a simple and representative electromechanical rotor model with physical variables and parameters.In this study, a new parametric model was derived for the unbalanced magnetic pull induced by an arbitrary rotor motion in transient operation. The parameters of this model can be determined analytically from the basis of the machine characteristics or estimated numerically as in this study. To estimate the parameters, an efficient numerical method was developed from the analysis of impulse response. The numerical results showed that the simple electromagnetic force model, together with the estimated parameters, predicts the unbalanced magnetic pull fairly accurately.An electromechanical rotor model was derived by combining the Jeffcott rotor model with the simple electromagnetic force model, including two additional variables for the harmonic currents of the rotor cage. Applying this model, the rotordynamic effects of electromechanical interaction were studied. Three induction motors were used in the numerical examples. The results obtained show that the electromechanical interaction may decrease the flexural frequen-4 cies of the rotor, induce additional damping or cause rotordynamic instability. These interaction effects are most significant in motors operating at, or near, the first flexural critical speed. Excluding the potential rotordynamic instability, the numerical results indicate that the electromechanical interaction effectively reduces the unbalance response close to the first flexural critical speed. 5 PrefaceThis work was carried out during the period 2001-2003 as a part of the research project "Electromechanical interaction in vibration control of electric machines". The aim of this project was to enhance our understanding of the effects of electromechanical interaction in general, and electromagnetic damping in particular, on the vibration control of electrical machines. The research partners were the

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“…Although, FEM gives accurate results, however, this method is time consuming especially for the analysis of electrical machines with asymmetry in the motor body such as air gap eccentricity. Moreover it requires an extensive characterization of the machine, for example, electromagnetic properties of all the materials making up the machine and the physical geometry [1,[7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Extension of Winding Function Theory for Radial and Axial Nonuniform Air Gap in Salient Pole Synchronous Machines

Akbari

Meshgin-Kelk²,

Milimonfared³

2011

PIER

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Abstract-In this paper, to calculate the salient pole machine inductances under radial and axial non-uniformity, a new method is developed. The method, an extension of the modified winding function theory to 3D, allows studying salient pole machines with radial and axial non-uniform air gap considering more realistic mean radius of the air gap. By using the developed method and a precise geometrical model, inductances of a salient pole machine with inclined rotor are calculated. Inductances are evaluated and effects of several asymmetries on inductances are shown. Calculated inductances are used in a coupled electromagnetic model, for simulation of a salient pole machine under healthy and different inclined eccentricity conditions. Simulation results show that the 19th stator current harmonic can be detected to alarm for inclined rotors. Experimental results that validate the theoretical and simulation results are presented.

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Effects of rotor eccentricity and parallel windings on induction machine behavior: a study using finite element analysis

Cited by 101 publications

References 3 publications

An Improved Analytical Model for Salient Pole Synchronous Machines Under General Eccentricity Fault

An Improved Analytical Model for Salient Pole Synchronous Machines Under General Eccentricity Fault

Electromechanical interaction in rotordynamics of cage induction motors

Extension of Winding Function Theory for Radial and Axial Nonuniform Air Gap in Salient Pole Synchronous Machines

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