• Title/Summary/Keyword: Magnetic Shield

Search Result 103, Processing Time 0.032 seconds

Linear Actuator using Magnetic Shield of Rotating Magnet Wheel (부분 자기 차폐된 마그네트 휠의 선형구동기로의 응용)

  • Shim, Ki-Bon;Park, Jun-Kyu;Lee, Sang-Heon;Jung, Kwang-Suk
    • Proceedings of the KSME Conference
    • /
    • 2008.11a
    • /
    • pp.923-925
    • /
    • 2008
  • As known generally, when permanent magnets whose poles are upward and downward in order, arranged into the circumferential direction rotate under the conducting plate, the rotating force acts on the plate as well as the repulsive force. If the magnetic field by the magnet wheel(the above rotating permanent magnets) is partially shielded, the magnet wheel over open region can be a linear induction motor. The distinct feature from induction motor is that the traveling magnet field is produced by the moving permanent magnet instead of ac current. Furthermore, a variation of the open region changes the direction of the thrust force. In this paper, we introduce a concept of the linear actuator using the magnet wheel. Under the above shielding condition, a few simulation results and its verification from a simple test setup are described.

  • PDF

EEM Analysis of Open-Typed Cylindrical Shieldcase (양끝이 열린 실드케이스의 FEM해석)

  • Kim, Young-Hak
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2017.05a
    • /
    • pp.767-769
    • /
    • 2017
  • Four-shell open-typed shield case was analyzed using 3D FEM. Analysis Dimension was $2m{\times}2m{\times}2m$. Length of shield case was 0.6m and its diameter was 0.1m, 0.08., 0.06m and 0.04m. Thickness and permeablility of shield case was all 1mm and 50,000. The excited magneic fields were earth magneic fields, which were 24A/m in the holizontal direction and 36A/m in the vertical direction, respectively. During FEM analysis, shield case was located at the direction of holizontal magnetic field and was rotated $90^{\circ}$. Magnetic field was $4.45{\times}10^{-2}A/m$ at the direction of holizontal magnetic field and $6.66{\times}10^{-4}A/m$ at the $90^{\circ}$ rotated direction.

  • PDF

Analysis of Electromagnetic Characteristics of a 1MW Class HTS Synchronous Motor (1MW급 고온초전도 동기기의 전자기적 특성 해석)

  • Baik, S.K.;Kwon, Y.K.;Lee, E.Y.;Lee, J.D.;Kim, Y.C.;Moon, T.S.;Park, H.J.;Kwon, W.S.
    • Progress in Superconductivity and Cryogenics
    • /
    • v.9 no.3
    • /
    • pp.32-36
    • /
    • 2007
  • On the contrary of a conventional motor with very narrow air-gap. it is difficult to calculate the accurate magnetic field distribution and the performance of an air-cored superconducting motor by 2 dimensional analysis. which does not use high permeability material except outer machine shield. This paper aims to do analysis of magnetic field and force distribution from the 3 dimensional modelling of a 1MW class superconducting synchronous motor. Especially. the field coil composed of Bi-2223 high-temperature superconductor and the outer machine shield are modelled by finite element analysis software according to their structures and the self-inductance and Lorentz force are calculated based on the 3 dimensional magnetic field calculation. Moreover. the influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power.

Magnetic Shielding Effect of Amorphous Strips in Low Frequency Field (비정질 연자성재료를 이용한 복층 차폐체의 저주파 자기장 차폐효과)

  • Kim, S.G.;Hur, J.;Park, P.G.;Chung, Y.C.;Kim, Y.B.;Kim, T.K.
    • Journal of the Korean Magnetics Society
    • /
    • v.8 no.6
    • /
    • pp.341-345
    • /
    • 1998
  • Magnetic shielding effect of cylinderical ahields made of commericial amorphous ribbons has been studied. The shell-arrangement-order of double shell shield has been found to show a striking differencein shielding factor. In low applied field region, a 2605CO-2705M-shield (outer shell: 2605CO, inner shell: 2705M) yields two times higher shielding factor than a 2705M-2605CO-shield (outer shell: 2705M, inner shell: 2605CO). The reasons are as follows: In case of 2605CO-2705M-shield, the outer shell is not easily saturated and effectively shields the applied field. In addition, the inner shell shows high shielding factor in the field shielded by the outer shell. In case of 2705M-2605CO-shield, the outer shell is saturated at very low-field as well as the inner shell shows low shielding factor in the field shielded by the outer shell.

  • PDF

Optimized Magnetic Shielding for the MagLev Vechicles (자기부상열차의 최적 자기 차폐)

  • 윤현보;박찬일;박희창;손영수;임계재
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.2 no.3
    • /
    • pp.17-25
    • /
    • 1991
  • Magnetic leakage flux which is generated from the levitation magnets, linear induction motors, and guide magnets of a MagLev(Magnetic Levitation) system is directly related to inter - system EMI, intra - system EMI, and biological effects. In this paper, the magnetic leakage flux from MagLev vechicles designed by Korea Resarch Institute of Ships & Ocean Engineering was calculated considering the various parameters which influence ma- gnetic field intensity around the MagLev system. Based on the calculated field intensity, the thickness of shielding material and shielding position for MagLev floor and side walls are calculated, taking into account the shielding effectiveness of a shield with minimum weight. For the nonuniform shielding method derived from the above procedure, the weight of a shield con- sisting of floor and side walls shielding can be reduced to more 50% than uniform shielding method.

  • PDF

Increased impedance by quench at a shield layer of HTS power cable for fault current limiting function

  • Choi, Youngjun;Kim, Dongmin;Cho, Jeonwook;Sim, Kideok;Kim, Sungkyu;Kim, Seokho
    • Progress in Superconductivity and Cryogenics
    • /
    • v.21 no.4
    • /
    • pp.59-63
    • /
    • 2019
  • To reduce the fault current below the current capacity of a circuit breaker, researches on HTS (High Temperature Superconductor) power cables with fault current limiting (FCL) function are increasing. An FCL HTS power cable transports current with low a impedance during normal operation. Yet, it limits the fault current by an increased inductive or resistive impedance of conducting layer when quench occurs at the FCL HTS power cable by the large fault current. An inductive type FCL HTS power cable uses increased inductive impendence caused by leakage magnetic flux outside the cable core when the quench occurs at a shield layer losing the magnetic shielding effect. Therefore, it has an advantage of less resistive heating than resistive type FCL HTS power cable and temperature increase is suppressed. This paper describes an ideal circuit model for the FCL HTS power cable to investigate the effectiveness of increased inductive impedance when quench occurs at the shield layer. Then, FEM analysis is presented with a simplified model cable composed of various iron yokes to investigate the effect of the shape of yoke on the generation of the inductive impedance.

E.M.F Characteristic of 30kVA class Superconducting Synchronous Generator according to Magnetic shield length (30kVA급 초전도 동기 발전기에서 축방향 길이 변화에 따른 유기기전력 특성연구)

  • Jo, Young-Sik;Hong, Jung-Pyo;Kim, Gyu-Tak;Kwon, Young-Kil;Ryu, Kang-Sik
    • Proceedings of the KIEE Conference
    • /
    • 1998.07a
    • /
    • pp.85-87
    • /
    • 1998
  • In general, we apply the 2 dimensional method to analyze the characteristic of electric machinery. But it is very difficult to analyze the air-cored machine like as superconducting generator, because it have 3 dimensional flux distribution. In this paper, we compare the analysis r between 2D and 3D. 3D Finite Element Meth applied to the superconducting generator at n condition. And we studied the characteristic acc to the axial length of magnetic shield.

  • PDF

OBSERVATION OF THE MAGNETIC DOMAIN IN THIN-FILM HEADS BY ELECTRON MICROSCOPY

  • Kobayashi, Kazuo
    • Journal of the Korean Magnetics Society
    • /
    • v.5 no.5
    • /
    • pp.710-715
    • /
    • 1995
  • Magnetic domains were observed using an image lock-in technique for backscattered electron contrast (Type II) with a 200 kV scanning electron microscope. Backscattered electrons indicate a difference in magnetic domain structures at the upper and lower parts of the upper pole in thin-film heads, changing the acceleration voltage. With this method, it is also possible to observe the domain structure of the thin-film head pole through a 10 to $20\;\mu\textrm{m}$ protective layer, and the upper shield of the MR head through the coil in the resist, alumina overcoat, and upper pole.

  • PDF