• Title/Summary/Keyword: 회전자기장

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Remote gas meter-reading system using magnetic sensor (자계 센서를 이용한 원격 가스 검침 시스템)

  • Koo, JaYl
    • Journal of the Institute of Electronics Engineers of Korea TE
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    • v.39 no.2
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    • pp.90-94
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    • 2002
  • This paper is related to remote meter-reading using magnetic sensor. Scan system which is developed recently has week point of temperature, humidity, dust, oscillation To solve these problems, this study used magnetic action to measure the consumption of gas. Gas consumption was detected by interaction of a permanent magnet and hall element. Permanent magnet was pasted on rolling change-gear in normal gas meter and hall sensor was pasted on the external wall of normal gas meter. This experiment proved high accuracy and wasn't influenced by temperature, humidity, oscillation and dust

Fiber-Optic Current Transformer for the Over Current Protection Relay (과전류 보호계전기용 광섬유 전류센서)

  • Song, Min-Ho;Yang, Chang-Soon;Ahn, Seong-Joon;Park, Byoung-Seok;Lee, Byoung-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.5
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    • pp.542-548
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    • 2001
  • A robust, accurate, broad-band, alternating current sensor using fiber-optics is being developed as a part of optical over current protection relay system. The sensor uses the Faraday effect in optical fiber and polarimetric measurements tc sense electrical current. The current sensing coil consists of a length of twisted optical fiber and Faraday rotator mirror to suppress the linear birefringence effect. Due to its single-ended closed path structure, it can not only be easily installed to the target with great isolation from other fields in the vicinity, but the sensitivity can be increased by using multiple turns. This paper reports on the theoretical backgrounds of the sensor design and the preliminary experimental results.

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ACQUISITION OF THE FLIGHT INFORMATION USING THE KSR-3 MAGNETOMETER (KSR-3 탑재 자력계를 이용한 비행정보 획득 연구)

  • Kim, Sun-Mi;Jang, Min-Hwan;Lee, Dong-Hun;Han, Young-Seok;Kim, Jun;Hwang, Seung-Hyun;Lee, Eun-Seok;Lee, Sun-Min;Kim, Hyo-Jin;Lee, Su-Jin
    • Journal of Astronomy and Space Sciences
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    • v.20 no.1
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    • pp.29-42
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    • 2003
  • The KSR-3 magnetometers consist of the fluxgate magnetometer (MAG/AIM) for acquiring the rocket flight attitude information, and the search-coil magnetometer (MAG/SIM) for the observation of the Earth's magnetic fluctuations. The position (latitude, longitude, and height) and flight condition (the transformation angle) of the rocket is measured after the data based on these two magnetometers are compared with IGRF The gap in the vector of magnetic field between the position of the launching point and an impact point is taken into account in data reduction. Angular variation of pitch, yaw, and roll can be researched when the data is applied to the coordinate system of the rocket.

Anisotropy Effect of Exchange Bias Coupling by Unidirectional Deposition Field of NiFe/FeMn Bilayer (NiFe/FeMn 이중박막의 증착시 자기장에 의한 교환결합력 이방성 효과)

  • Park, Young-Seok;Hwang, Do-Guwn;Lee, Sang-Suk
    • Journal of the Korean Magnetics Society
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    • v.18 no.5
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    • pp.180-184
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    • 2008
  • The relation of ferromagnet anisotropic magnetization and the antiferromagnet atomic spin configuration has been investigated for variously angles of unidirectional deposition magnetic field of FeMn layer in Corning glas/Ta(5 nm)/NiFe(7 nm)/FeMn(25 nm)/ Ta(5 nm) multilayer prepared by ion beam deposition. Three unidirectional deposition angles of FeMn layer are $0^{\circ},\;45^{\circ}$, and $90^{\circ}$, respectively. The exchange bias field ($H_{ex}$) obtained from the measuring easy axis MR loop was decreased to 40 Oe in deposition angle of $45^{\circ}$, and to 0 Oe in the angle of $90^{\circ}$. One other side hand, $H_{ex}$ obtained from the measuring hard axis MR loop was increased to 35 Oe in deposition angle of $45^{\circ}$, and to 79 Oe in the angle of $90^{\circ}$. Although the difference of uniderectional axis between ferromagnet NiFe and antiferromagnet FeMn was 90o, the strong antiferromagnetic dipole moment of FeMn caused to rotate the weak ferromagnetic dipole moment of NiFe in the interface. This result implies that one of origins for exchange coupling mechanism depends on the effect of magnetic field angle during deposition of antiferromgnet FeMn layer.

Robust Stability Analysis of Hybrid Magnetic Bearing System (하이브리드 자기베어링 시스템의 강인 안정도 해석)

  • Sung, Hwa-Chang;Park, Jin-Bae;Tark, Myung-Hwan;Joo, Young-Hoon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.21 no.3
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    • pp.372-377
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    • 2011
  • This paper propose the robust stability algorithm for controlling a hybrid magnetic bearing system. The control object in the magnetic bearing system enables the rotor to rotate without any physical contact by using magnetic force. Generally, the system dynamics of the magnetic bearing system has severe nonlinearity and uncertainty so that it is not easy to obtain the control objective. For solving these problems, we propose the fuzzy modelling and robust control algorithm for hybrind magnetic bearing system. The sufficient conditions for robust controller are obtained in terms of solutions to linear matrix inequalities (LMIs). Simulation results for HMB are demonstrated to visualize the feasibility of the proposed method.

Development of Magnetic Torquer for Satellite Attitude Control (인공위성 자세제어용 Magnetic Torquer 개발)

  • Son, D.
    • Journal of the Korean Magnetics Society
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    • v.18 no.2
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    • pp.54-57
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    • 2008
  • Magnetic torquer, which uses torque between magnetic dipole moment and earth magnetic field, has been used to control attitude of satellites. In this work, we developed a magnetic torquer for small scientific satellite and test under environmental conditions of the satellite launching and orbital motion have been carried out. The developed magnetic torquer shows saturation magnetic dipole moment of $15Am^2$, linearity of 0.3 % in the range of ${\pm}12Am^2$, mass of 0.46 kg, and power consumption of 1 Watt at magnetic dipole moment of $10Am^2$.

Development of Lorentz Force Type Integrated Motor-Bearing System in Dual Rotor Disk Configuration (두 장의 원판형 회전자를 갖는 로렌츠형 자기 베어링 내장 전동기의 개발)

  • Park, Sung-Ho;Lee, Chong-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.935-940
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    • 2005
  • In this paper, dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor bearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation method effectively attenuates the rotor vibration all over the operating range of rotational speed.

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Development of Lorentz Force Type Integrated Motor-bearing System in Dual Rotor Disk Configuration (두 장의 원판형 회전자를 갖는 로렌츠형 자기 베어링 내장 전동기의 개발)

  • Lee, Chong-Won;Park, Sung-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.9 s.102
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    • pp.1045-1052
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    • 2005
  • Tn this paper. dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor hearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation scheme effectively attenuates the rotor vibration all over the operating range of rotational speed.

Characteristics of the Angular-dependent Exchange Coupling Bias in Multilayer [Pt/Co]N-IrMn with Toward-in Plane Applied Fields (박막수직방향에서 면방향으로 회전하는 인가자기장에 대한 다층박막 [Pt/Co]N-IrMn의 교환바이어스의 각도의존특성)

  • Kim, S.S.;Yim, H.I.;Rhee, J.R.;Lee, S.S.;Hwang, D.G.
    • Journal of the Korean Magnetics Society
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    • v.18 no.4
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    • pp.142-146
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    • 2008
  • The angular dependence of the exchange bias($H_{ex}$) and coercivity($H_c$) in multilayer $[Pt/Co]_N-IrMn$ with applied measuring field rotated toward in-plane at angle $\theta$ from perpendicular-to-plane, has been measured. Multilayer films consisting of $Si/SiO_2/Ta(50)/Pt(4)/[Pt(15)/Co(t_{Co})]_N/IrMn(50)/Ta(50)(in\;{\AA})$ were prepared by magnetron sputtering under typical base pressure below $2{\times}10^{-8}$ Torr at room temperature. Magnetization measurements were performed on a vibrating sample magnetometer and extraordinary Hall voltage measurement systems after cooling from 550 K under a field of 2 kOe applied along the perpendicular to film direction. The hysteresis loop shifts from the origin not only along the field axis but also along the magnetization axis. $H_{ex}$ and $H_c$ show a $1/cos{\theta}$ and $1/|cos{\theta}|$ dependence on the angle($\theta$) between the applied measuring field and the perpendicular-film direction, respectively. This $1/cos{\theta}$ dependence can be accounted for by considering the angular dependence of strong out-of-plane magnetic anisotropy introduced during the field cooling.

Magnetic analysis of a finite solenoid (유한 솔레노이드의 자속밀도 해석)

  • Lee, Ju-Hee;Hwang, Seon;Lee, Dong-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.10
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    • pp.6453-6457
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    • 2015
  • In this paper, the theoretical analysis for a solenoid with a finite length was verified by the finite element simulation. The solenoids are widely being used in the field of mechanical, industrial, medical industry due to their simple structure and fast responses. Solenoid actuators use an electromagnetic force. A magnetic field is formed around the solenoid coil when a current is applied. The magnetic force generated by the magnetic field enables an inside plunger to move linearly. The axial and radial magnetic fields (magnetic flux density, B) at a certain point were calculated from the Biot-Savart's law and compared with the simulation analysis from the ANSYS-Magnetostatic S/W. Comparison result, an error exists in the error range, and could therefore verify the accuracy.