• Title/Summary/Keyword: 불평형 응답 해석

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Unbalance Response Analysis of Copper Die Casting High Speed Induction Motor (동 다이캐스팅 고속 유도전동기의 불평형 응답 해석)

  • Hong, Do-Kwan;Jung, Seung-Wook;Woo, Byung-Chul;Koo, Dae-Hyun;Ahn, Chan-Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.7
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    • pp.642-649
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    • 2012
  • This paper deals with a copper die casting induction motor which has several advantages of motor performance. The developed motor is used as spindle motor in machining center. The dynamic characteristic analysis of rotor is dealt with for precision machining. The critical speed of rotor considering rotation and gyroscopic effect should be above operating speed, 18,000 rpm, and have a 201 % sufficient separation margin. Also, the 3-D unbalance vibration response analysis is performed and enabled the prediction of the expected vibration amplitude by unbalance in high speed. The unbalance vibration responses of each position on the rotor are satisfied with allowable vibration displacement of API 611 standard according to balancing G grade(G 0.4, G 2.5, G 6.3). Copper die casting high speed induction motor is successfully developed and verified by experiment.

Unbalance Response Analysis of Induction Motor Rotor Considering Unbalanced Electromagnetic Forces (불평형 전자기력을 고려한 유도전동기 회전자의 불평형 응답해석)

  • 손병구
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.2
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    • pp.201-209
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    • 1999
  • This paper presents a general analytical method for analyzing mechanical unbalance response of unbalanced electromagnetic forces produced in induction motors with an eccentric rotor and a phase unbalance. The equations to be solved are a set of second order differential equations which give matrices with periodic coefficients that are a function of time due to the unbalanced electro-magnetic force. Unbalance response is processed by Newmark $\beta$ method. Two examples are given including an industrial application. The results show that the method proposed is satisfactory.

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Critical Speed Analysis of the Liquid Rocket Turbopump (액체로켓 터보펌프의 임계 속도 해석)

  • Jeon, Seong-Min;Kwak, Hyun-Duck;Yoon, Suk-Hwan;Kim, Jin-Han
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.6
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    • pp.92-99
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    • 2005
  • Numerical analyses of critical speed and mass unbalance response are performed for a 30 ton thrust turbopump. The stiffness and damping of ball bearings and non-contact seals are quantified under aerodynamic and hydrodynamic loads induced by a fuel pump and turbine. Critical speed margin and tip displacements of the rotating parts are evaluated using a three-dimensional finite element method. The results are used to ensure the soundness of the rotordynamic design using an one-dimensional transfer matrix method. A further study shows that sufficient resonance margin may be assured via controlling the stiffness of the rotor support by employing an additional elastic ring to the bearing support.

Finite Element Analysis of Unbalance Response of a High Speed Flexible Polygon Mirror Scanner Motor with Asymmetric Finite Element Equations (비대칭 유한 요소 방정식으로 표현되는 고속 유연 폴리곤 미러 스캐너 모터의 유한 요소 불평형 응답 해석)

  • Seo, Chan-Hee;Jung, Kyung-Moon;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1022-1027
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    • 2007
  • This paper presents a method to analyze the unbalance response of a high speed polygon mirror scanner motor supported by sintered metal bearing and flexible structures by using the finite element method and the mode superposition method considering the asymmetry of the gyroscopic effect and sintered metal bearing. The eigenvalues and eigenvectors are calculated by solving the eigenvalue problem and the adjoint eigenvalue problem by using the restarted Arnoldi iteration method. The decoupled equations of motion can be obtained from global finite element motion equations by using the orthogonal relation between the right eigenvectors and left eigenvectors. The decoupled equations of motion are used to analyze the unbalance response of a high speed polygon mirror scanner motor. The validity of the proposed method is verified by comparing the simulated unbalance response with the experimental results.

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Finite Element Analysis of Unbalance Response of a High Speed Flexible Polygon Mirror Scanner Motor Considering the Flexibility of Supporting Structure (지지구조의 유연성을 고려한 고속 유연 폴리곤 미러 스캐너 모터의 유한 요소 불평형 응답 해석)

  • Jung, Kyung-Moon;Seo, Chan-Hee;Kim, Myung-Gyu;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.859-865
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    • 2007
  • This paper presents a method to analyze the unbalance response of a high speed polygon mirror scanner motor supported by sintered bearing and flexible supporting structures by using the finite element method and the mode superposition method. The appropriate finite element equations for polygon mirror are described by rotating annular sector element using Kirchhoff plate theory and von Karman non-linear strain, and its rigid body motion is also considered. The rotating components except for the polygon mirror are modeled by Timoshenko beam element including the gyroscopic effect. The flexible supporting structures are modeled by using a 4-node tetrahedron element and 4-node shell element with rotational degrees of freedom. Finite element equations of each component of the polygon mirror scanner motor and the flexible supporting structures are consistently derived by satisfying the geometric compatibility in the internal boundary between each component. The rigid link constraints are also imposed at the interface area between sleeve and sintered bearing to describe the physical motion at this interface. A global matrix equation obtained by assembling the finite element equations of each substructure is transformed to a state-space matrix-vector equation, and both damped natural frequencies and modal damping ratios are calculated by solving the associated eigenvalue problem by using the restarted Arnoldi iteration method. Unbalance responses in time and frequency domain are performed by superposing the eigenvalues and eigenvectors from the free vibration analysis. The validity of the proposed method is verified by comparing the simulated unbalance response with the experimental results. This research also shows that the flexibility of supporting structures plays an important role in determining the unbalance response of the polygon mirror scanner motor.

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A Study on the Turbopump Rotordynamic Characteristics due to Bearing Housing Structural Flexibility (베어링 하우징의 구조 유연성에 따른 터보펌프 회전체동역학 특성 연구)

  • Jeon, Seong Min;Yoon, Suk-Hwan;Kim, Jinhan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.2
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    • pp.35-41
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    • 2014
  • A rotordynamic analysis is performed for a turbopump of 7 ton class liquid rocket engine considering bearing housing structural flexibility. Stiffness and damping characteristics of ball bearings and pump noncontact seals are reflected in a rotordynamic model. A dynamic model of bearing housing with lumped mass and stiffness is also applied to the rotordynamic analysis. Rotor critical speed and onset speed of instability are predicted from synchronous rotor mass unbalance response and complex eigenvalue analyses. The bearing housing structural flexibility effect on rotordynamic characteristics is investigated for both of bearing loaded and unloaded conditions respectively. From the numerical analysis, it is found that the effect of the housing structural flexibility significantly reduces the rotor critical speed and onset speed of instability.