• Title/Summary/Keyword: external magnetic field

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Torque Analysis of Magnetic Spur Gear with Radial Magnetized Permanent Magnets based on Analytical Method (해석적 방법을 이용한 반경방향 영구자석을 갖는 자기 스퍼 기어의 토크특성해석)

  • Min, Kyoung-Chul;Choi, Jang-Young;Sung, So-Young;Park, Jong-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.4
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    • pp.545-551
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    • 2015
  • This paper deals with torque analysis of magnetic spur gear with radial magnetized permanent magnets based on analytical method. The analysis is implemented in three parts: First, on the basis of magnetic vector potential and a two-dimensional (2D) polar-coordinate system, the magnetic field solution due to permanent magnet of source gear are obtained. And by using derived magnetic field solutions, the analytical solutions for external magnetic field distribution which affects load gear are obtained. Second, by using coordinate conversion, external magnetic field which is on the primary coordinate system is converted to the secondary coordinate system. Finally, the load gear is reduced to equivalent current densities, and the torque is computed on these currents in the external field of the source magnet. These analytical results are validated by comparing with the 2-D finite element analysis (FEA).

Flow Visualization of Magnetic Particles under the external magnetic field in bubbly flow using Single Plane Illumination Microscopy - MicroPIV (Single Plane Illumination Microscopy - MicroPIV를 이용한 버블 유동에서 외부 자계 영향을 받는 자성입자 가시화)

  • Lee, Changje;Cho, Gyeong-rae;Lee, Sangyoup
    • Journal of the Korean Society of Visualization
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    • v.19 no.1
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    • pp.36-42
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    • 2021
  • This study measured the velocity of magnetic particles inside the power generation using external heat sources. Single Plane Illumination Microscopy (SPIM) was used to measure magnetic particles that are simultaneously affected by bubbly flow and magnetic field. It has the advantage of reducing errors due to particle superposition by illuminating the thin light sheet. The hydraulic diameter of the power generation is 3mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 200nm. The excitation and emission wavelengths are 530 and 650nm, respectively. In order to find out the flow characteristics, a total of four velocity fields were calculated in wide and narrow gap air bubbles, between the wall and the air bubble and just below the air bubble. Magnetic particles showed up to 8.59% velocity reduction in the wide gap between air bubbles due to external magnetic field.

Dependence of External Magnetic Field in the Matrix-Type SFCL with the Separated or the Integrated Reactors (분리형과 일체형 리액터에 따른 매트릭스형 초전도 한류기의 외부자장 의존성 연구)

  • Cho, Yong-Sun;Choi, Hyo-Sang;Jung, Byoung-Ik;Go, Sung-Pil
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.880-884
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    • 2011
  • The matrix-type superconducting fault current limiter (MSFCL) consists of the trigger and current-limiting parts. The trigger part with reactors connected in parallel improves the quenching characteristics by applying the external magnetic field into the superconducting units. The current-limiting part with superconducting units connected in parallel and shunt reactors connected in series limit the fault current when the fault occurs. We developed the integrated reactor with the trigger and the current-limiting parts to apply high external magnetic field into the superconducting units. This was composed of a superconducting unit for the trigger part and two superconducting units for the current-limiting parts. We confirmed that the external magnetic field generated in the MSFCL with an integrated reactor was larger than that of the MSFCL with the separated reactors. So the differences of voltages generated between superconducting units were decreased in the difference according to the increment of the applied voltage. The whole magnitude of the SFCL was reduced because the volume of an integrated reactor could be reduced by one-third than that of the separated reactors. We confirmed that the critical behavior between the superconducting units in the MSFCL with an integrated reactor was more improved than that of the MSFCL with the separated reactors.

GMI Magnetic Field Sensor based on Time-coded Principle

  • Cao, Xuan-Huu;Son, De-Rac
    • Proceedings of the Korean Magnestics Society Conference
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    • 2009.12a
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    • pp.217-219
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    • 2009
  • A GMI magnetic field sensor working based on time-coded principle has been investigated and designed. The laboratory model has been constructed and tested carefully, demonstrating the sensitivity of $3\;{\mu}s/{\mu}T$ in the field range of ${\pm}100\;{\mu}T$. An amorphous thin wire, $100\;{\mu}m$ in diameter ${\times}50\;mm$ in length, was chosen to be sensing element which was fit into a small field modulation coil of 60 mm in length. The sensor is working based on a time-coded principle that, with the magnetic field modulation was chosen in range of hundreds of Hz, the change in time interval of two adjacent GMI peaks relating to external DC magnetic field is proportional to the intensity of the external field to be measured. This mechanism has made a great improvement to the linearity of the sensor.

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Influence of axial magnetic field on the plasma density on the substrate in helical resonator (헬리칼 공명 플라즈마의 기판플라즈마밀도에 미치는 축방향자계의 영향)

  • Kim, Tae-Hyun;Kim, Moon-Young;Jang, Sang-Hun;Tae, Heung-Sik
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.376-378
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    • 1997
  • Plasma density and its axial distribution and uniformity on the substrate in a helical resonator plasma in the external magnetic field have been measured using Langmuir probes. Net RF power is set to 200W and chamber pressure is varied from $1{\times}10^{-1}Torr$ to $1{\times}10^{-4}Torr$. There are three kinds of external magnetic field structure applied on the helical resonator plasma. One is a uniform magnetic field, another is a plus gradient magnetic field and the third is a minus gradient magnetic field. Of the three magnetic field structure, the minus gradient magnetic field is found to show the highest increase in plasma density on the substrate compared with other magnetic structures. In order to avoid radial density ununiformity, weak magnetic fields under 100Gauss are applied.

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Analysis of the stresses induced by magnetic field and cooling in the CICC type superconducting bus-line (CICC 형태의 초전도 버스 선에서 냉각 및 자기장에 의한 응력 해석)

  • Lee, Ho-Jin;Nam, Hyeon-Il;Kim, Gi-Baek;Hong, Gye-Won
    • Progress in Superconductivity and Cryogenics
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    • v.2 no.2
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    • pp.20-25
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    • 2000
  • A CICC type superconducting bus-line electrically connecting a superconducting magnet to a power supply is cooled down to low temperature under the external magnetic field during operation. The thermal contraction during the cooling may be constrained by the supports which are installed to protect the bus-line from Lorenz magnetic forces. This constrained contraction causes thermal stresses in the bus-line to release thermal contraction. The minimum stress conditions in the bus-line may be optimized by controlling the supporting arrangement considering the thermal contraction and the external field. The analytical method to find optimal supports arrangement was suggested by using the beam theory, and numerical calculation using commercial code was performed to verify the suggested analytical optimization method.

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Influence of external magnetic field on HTS cable conductor (외부 자계 인가에 따른 고온초전도 케이블 도체의 ?치 특성)

  • Seong Woo Yim;Si Dole Hwang;Je Myoung Oh;Byung Sung Han
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.284-287
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    • 2003
  • Quench characteristics of HTS cable conductor due to external magnetic field were investigated. Firstly, the influence of critical characteristics of HTS tape on locally applied magnetic field was examined. Secondly, critical current of HTS tapes, which are wound on surface of former, were measured respectively, before the experiment for quench characteristics, Finally, 50mT and 100mT were applied to HTS cable conductor and quench characteristics were investigated through V-I curves. As the results, same as the result of HTS tape, HTS cable conductor showed strong dependence on external magnetic field with direction and magnitude.

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Comparison of Magnetization Losses in BSCCO Tape and YBCO CC at Arbitrary Direction of External Magnetic Field (BSCCO Tape 선재와 YBCO CC의 외부자장 각도에 따른 자화손실 특성비교)

  • Lee Ji-Kwang;Lim Hyung-Woo;Park Myung-Jin;Cha Gueesoo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.12
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    • pp.586-591
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    • 2005
  • Magnetization loss of high temperature superconductoring BSCCO tape and YBCO coated conductor(YBCO CC) is most important issue in the development of superconducting power devices. In this paper, the measured results of magnetization losses in BSCCO tape and YBCO CC are presented and compared with each other. Measurements of magnetization losses are performed under various angles of external magnetic field to consider the anisotropic characteristics of YBCO CC. Also, we present the compared results of magnetization losses measured at arbitrary directional magnetic fields and analyzed with perpendicular magnetic field components of those. The results show that magnetization loss of YBCO CC agree well with the analyzed value by it's perpendicular magnetic field component, but BSCCO tape is not.

Angle Sensors Based on Oblique Giant Magneto Impedance Devices

  • Kim, Do-Hun;Na, Ji-Won;Jeung, Won-Young
    • Journal of Magnetics
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    • v.14 no.1
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    • pp.42-46
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    • 2009
  • The measurement of external magnetic field orientation using Giant Magneto Impedance (GMI) sensors has been performed. A soft magnetic alloy of $Co_{30}Fe_{34}Ni_{36}$ was electroplated on a Si wafer with a CoFeNi seed layer. V-shaped microwire patterns were formed using a conventional photolithography process. An external magnetic field was generated by a rectangular AlNiCo permanent magnet. The reference direction was defined as the external magnetic field direction oriented in the middle of 2 GMI devices. As the orientation of the magnetic field deviated from the reference direction, variation in the field component along each device introduced voltage changes. It was found that, by taking the voltage difference between the left and right arms of the Vshaped device, the nonlinearity of each device could be significantly reduced. The fabricated angle sensor had a linear range of approximately $70^{\circ}$ and an overall sensitivity of approximately 10 mV.

Transport Loss Characteristics of a Bi-2223 Tape in External AC Magnetic Fields (외부 교류지장에 대한 Bi-2223테이프의 통전손실 특성)

  • Ryu, Kyung-Woo;Kim, Chang-Wan;Cha, Guee-Soo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.6
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    • pp.290-295
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    • 2001
  • The transport loss of a Bi-2223 tape exposed to external magnetic fields was investigated. The results show that the transport loss is independent on voltage lead arrangements in case the magnetization loss is compensated. A serous increase of the transport loss due to external AC magnetic field is observed. The loss is described well by dynamic resistance loss in relatively high fields, but another mechanism than the dynamic resistance must be responsible for the increase of the loss in low fields. The transport loss is also dependent strongly on the orientation of the external fields.

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