• Title/Summary/Keyword: Linear motors

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The optimum geometric design of stators for brush less DC linear motors (브러시없는 직류 선형 모터의 고정자 형상 최적 설계)

  • 최문석;김용일;이상락
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.1173-1176
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    • 1995
  • We design and analyze two type stators for brushless DC linear motors by the experiment and the computational analysis. For a U-shape stator, the maximum manetic flux density by the finite element method(FEM) is large than that by the experiment by 1.0~2.2%. The result by the FEM is so accurate that it can be applied to the geometric design for the optimization. To increase the maximum magnetic flux density, we suggest an improved stator and analyze it by the 3-D and 2-D models. The maximum magnetic flux density of the improved stator is large than that of the U-Shape stator by 2.7%. Considering the size of the improved stator and maximum magnetic flux density, we determine that the optimized thickness is 5mm for a given specification.

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Linear stability analysis in a solid-propellant rocket motor (고체추진 로켓모터에서의 선형 안정성 해석)

  • ;;Kim, Kyung-Moo;Yoon, Jae-Kun
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.10
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    • pp.2637-2646
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    • 1995
  • Combustion instability in solid-propellant rocket motors depends on the balance between acoustic energy gains and losses of the system. The objective of this paper is to demonstrate the capability of the program which predicts the standard longitudinal stability using acoustic modes based on linear stability analysis and T-burner test results of propellants. Commercial ANSYS 5.0A program can be used to calculate the acoustic characteristic of a rocket motor. The linear stability prediction was compared with the static firing test results of rocket motors.

Air Gap Change of a Maglev Vehicle at the Moment a Linear Induction Motor Runs (자기부상열차 가속 순간 부상공극 변화)

  • Shin, Hyeon-Jae;Han, Hyung-Suk;Kim, Dong-Sung;Kim, Bong-Seup
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.1218-1223
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    • 2009
  • LIM(Linear induction motor)s are the main type of motors used for urban Maglev vehicles because they are less expensive to operate at a lower speed than linear synchronous motors. An LIM generates an attraction force while running, which perturbs the air gap of the electromagnet. This undesirable air gap variation could result in the mechanical contact of an electromagnet with the reaction plate. For this reason, the magnitude of the air gap variation must be limited within a certain range. The air gap changes when running the 1/2 vehicle under development for testing are analyzed through a test on the test track at KIMM. The results from this study could be used to minimize the air gap variations due to attraction force from LIM.

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Sliding Mode Control with the feedback linearization and novel sliding surface for induction motors (새로운 슬라이딩 평면과 궤환 선형화를 이용한 유도 전동기의 슬라이딩 모드 제어)

  • Park, Seung-Kyu;Ahn, Ho-Kyun;Kim, Hyung-Moon
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2672-2674
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    • 2000
  • In this paper. feedback linearization and the sliding mode control(SMC) are used together for uncertain nonlinear system. An advantage of feedback linearization technique is to make linear control theories can be used for nonlinear system and the SMC have the robustness. But the dynamics of the SMC has the dynamics lower order than that of the original system. Therefore the linear control theory can not be used with the SMC. The novel sliding surface of the SMC can have the dynamics of the nominal non linear system controlled by the feedback linearization. The proposed method can be used for the control of induction motors.

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Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • 김석일;조재완
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.416-423
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

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Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • Kim Seok-ll;Cho Jae-Wan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.5
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    • pp.30-37
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

The Permeance Estimation and Characteristic Analysis of the Hybrid Stepping Motors Considering the Saturation (Hybrid Stepping Motor의 포화를 고려한 퍼미언스 산정 및 특성해석)

  • Woo, Joon-Keun;Lim, Ki-Chae;Hong, Jung-Pyo;Kim, Kyu-Tak
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.885-887
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    • 2000
  • The paper proposes the characteristic analysis method to consider the saturation of teeth and poles in the hybrid stepping motors. The proposed method is based on the equivalent magnetic circuit coupling with the finite element analysis. The equivalent magnetic circuit is used to analysis the characteristics of the hybrid stepping motors. And the FE analysis is used to compute the non-linear parameters included the equivalent magnetic circuit in the hybrid stepping motors. Simulation and experiment results show that the proposed technique is compared with the classical method.

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