Eccentrically mounted rotor pack and its influence on the vibration and noise of an asynchronous generator

Donát, Martin; Dušek, Daniel

doi:10.1016/j.jsv.2015.01.033

Cited by 11 publications

(8 citation statements)

References 11 publications

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“…Two common approaches are the analytical method and the finite element method (FEM). Although the FEM has been widely applied to study the UMF [6,7], the analytical method still receives much attention because insights into the origins and pivotal factors in the production of UMF is provided by this method. Earlier publications focused primarily on the theoretical formulation of UMF and linear equations were mainly adopted.…”

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confidence: 99%

Review of Electromagnetic Vibration in Electrical Machines

Han

Chu

2018

Energies

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Electrical machines are important devices that convert electric energy into mechanical work and are widely used in industry and people's life. Undesired vibrations are harmful to their safe operation. Reviews from the viewpoint of fault diagnosis have been conducted, while summaries from the perspective of dynamics is rare. This review provides systematic research outlines of this field, which can help a majority of scholars grasp the ongoing progress and conduct further investigations. This review mainly generalizes publications in the past decades about the dynamics and vibration of electrical machines. First the sources of electromagnetic vibration in electrical machines are presented, which include mechanical and electromagnetic factors. Different types of air gap eccentricity are introduced and modeled. The analytical methods and numerical methods for calculating the electromagnetic force are summarized and explained in detail. The exact subdomain analysis, magnetic equivalent circuit, Maxwell stress tensor, winding function approach, conformal mapping method, virtual work principle and finite element analysis are presented. The effects of magnetic saturation, slot and pole combination and load are discussed. Then typical characteristics of electromagnetic vibration are illustrated. Finally, the experimental studies are summarized and the authors give their thoughts about the research trends.Energies 2018, 11, 1779 2 of 33 vibration mechanism can be helpful for the design of electrical machines. Therefore, the study of the electromagnetic vibration of electrical machines has practical significance.Electromagnetic vibrations are usually generated by the distorted air-gap field of an eccentric rotor in electrical machines. The uneven air-gap is directly related to the eccentricity, which is common in rotating electrical machines. Eccentricity can be caused by several reasons, such as relative misalignment of the rotor and stator in the fixing stage, misalignment of the load axis and rotor shaft, elliptical stator inner cross section, wrong placement or rubbing of ball bearings, mechanical resonance, and unbalanced loads [1,2]. Eccentricities can be further subdivided into two categories: circumferential unequal air gaps and axial unequal air gaps. The former can be grouped into static eccentricity and dynamic eccentricity. In the case of static eccentricity, the rotor rotates around its own geometric axis, which is not the geometric axis of the stator. In the case of dynamic eccentricity, the rotor is not concentric and rotates around the geometric axis of the stator. In reality, both static eccentricity and dynamic eccentricity tend to coexist. An inherent static eccentricity exists, even in newly manufactured machines, due to the build-up of tolerances during the manufacturing and assembly procedure, as has been reported in [3]. Unequal air gaps cause unbalanced magnetic forces (UMFs) [4] on the rotor, which lead to mechanical stress on some part of the shaft and bearing. After prolonged operation, these fac...

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confidence: 99%

Review of Electromagnetic Vibration in Electrical Machines

Han

Chu

2018

Energies

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“…Three parameters are introduced to describe the mechanical behavior of the material of the studied generator: Poisson ratio, density and Young modulus. Since the stator coils are electrically insulated by a layer of varnish and covered by resin, and the stator core consists of lots of thin sheets with slots for the coils which are compressed into packets, the material of the stator pack cannot be considered to be homogeneous or isotropic, therefore the model of the core is simplified to a cylinder and the coils were modelled as rods with reduced Young's modulus [2]. The material characteristics of the stator model are shown in Table 3.…”

Section: A 3d Stator Model For Mechanical Analysismentioning

confidence: 99%

“…Many studies have been done to investigate the vibration of stator in the past decades, which can be classified into two categories: theoretical research and engineering application. Theoretical research mainly includes mathematical modeling, structure characteristic calculation, and dynamic response predicting using analytic or numerical method [1][2][3]. Engineering application mainly focuses on the vibration analysis technique, fault diagnosis technology and elimination solution [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Finite Element Analysis to Investigate the Vibration of Oblique-Stud Stator Frame in a Large Hydropower Generator Unit

Zhou

Peng

et al. 2017

Energies

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This paper presents an investigation on the undesirable vibration of an oblique-stud stator frame in a large hydropower generator by means of experimental and finite element (FE) analysis. First, field experimental tests were performed, and the results indicate that the main vibration component comes from electromagnetic factors. Then, a 2D-magnetic and 3D-mechanical FE model was developed to investigate the vibration of the stator frame under the action of electromagnetic forces. A set of contrast models was established to study the effects of different kinds of eccentricity and different structures. Based on the comparative analysis between the results of simulations and experimental tests, it can be inferred that the abnormal vibration is generated because of the lack of stiffness in the upper part of structure and the existence of dynamic eccentricity in the rotor-stator system. In addition, the structural simulation analysis shows that the flexible designed oblique-stud stator frame is relatively vulnerable against the electromagnetic forces.

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“…The approximate analytical method and numerical method are used frequently. Donát M. noticed the influence of rotor eccentricity on the vibration and noise, and calculated the electromagnetic force and its dynamic response in asynchronous generator [1]. Besnerais J.…”

Section: Introductionmentioning

confidence: 99%

The study on magnetism and solid coupling vibration and its electromagnetic force characteristics in stator system of electrical machine

Li¹,

Jian-xin²,

Xiaohua³

et al. 2018

Vib. proced.

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The air-gap electromagnetic force is not the unique excitation which excites magnetism and solid coupling vibration on stator system of asynchronous machine. Besides, there should be a ponderomotive force as an internal electromagnetic excitation in stator core. Therefore, the magnetism and solid coupling vibration equation with both of the forces was obtained for the electromagnetically excited vibration on stator system of electrical machine. Based on Maxwell equations and the electromagnetic constitutive relation, the expressions of the electromagnetic field and force were derived by solving the eddy equation and the boundary conditions. With numerical calculation, the influences of geometric parameters on the electromagnetic field and forces were analyzed. The electromagnetic excitations of magnetism and solid coupling vibration on stator system were improved by the analysis of ponderomotive force in the stator core. Furthermore, the conclusions provide a theoretical basis for the electromagnetic design of asynchronous machine.

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Eccentrically mounted rotor pack and its influence on the vibration and noise of an asynchronous generator

Cited by 11 publications

References 11 publications

Review of Electromagnetic Vibration in Electrical Machines

Review of Electromagnetic Vibration in Electrical Machines

Experimental and Finite Element Analysis to Investigate the Vibration of Oblique-Stud Stator Frame in a Large Hydropower Generator Unit

The study on magnetism and solid coupling vibration and its electromagnetic force characteristics in stator system of electrical machine

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