• Title/Summary/Keyword: Faraday Effect

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A Study on High Voltage and High Current Measurement using Laser (레이저에 의한 고전압 및 대전류 측정에 관한 연구)

  • Gang, Hyeong-Bu;Jeong, Un-Gwan;Jang, Yong-Mu;Choe, Seung-Gil;Sim, Jae-Hak
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.769-770
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    • 1988
  • The Pockel's effect is well know as a voltage measurement method. This method is applicable to high voltage measurement equipments. We observe the Faraday rotation of the polarization plane in the current-induced magnetic field.

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A Study on Direct Current Measurement Using Magneto-Optical LMF Method (자기장학 누설자속법을 응용한 직류전류계측법에 관한 연구)

  • Lee, Jin-Yi
    • Journal of the Korean Society for Nondestructive Testing
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    • v.24 no.6
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    • pp.566-572
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    • 2004
  • It is necessary to measure the direct current with a non-contact methodology for the liquid or gas phase, as welt as the conducting metals. This paper described a theoretical consideration and experimental verification for a non-contact quantitative direct current measurement system using the Faraday effect and magnetic flux leakage. The leakage of magnetic flux occurs around a gap when a ferromagnetic core including the discontinuous gap is magnetized. Two large anisotropic domains in a magneto-optical film are occurred by the vertical component of leaked magnetic flux and the domain walls are paralleled to the center of the gap. Here, the symmetrical arrangement of domains are deflected when a vertical magnetic field is applied to the magneto-optical film. The domain wall of the magneto-optical film are relocated when a measuring current passes through the ferromagnetic core. Therefore, a direct current passing through the core can be determined quantitatively by the measurement of moving distance of the domain wall.

Clamp-type Bulk Optic Current Sensor (클램프헝 부피 광 전류센서)

  • Chung, Hyun;Lee, Yong-Wook;Kim, Soo-Gil;Lee, Byoung-Ho;Park, Byoung-Seok
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1924-1926
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    • 2002
  • The optical current transformer using Faraday effect is the sensor to measure current that flows in any conductor. This sensor doesn't undergo the magnetic saturation and effect of adjacent conductors. But this senor using bulk-glass sensing clement has crucial drawback. It is impossible that the sensor is mounted to conductor without breaking the closed-loop of light or conductor. So we developed the clamp-type optical current transformer and made an experiment.

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The Study of the Optical Current Sensor Using Magneto-Optic Effects (자기광학효과를 이용한 광전류센서에 관한 연구)

  • 전재일;이정수;송시준;정철우;박원주;이광식;김정배;김민수
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.6
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    • pp.47-53
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    • 2003
  • In this paper, we described the laboratory layout of the optical CT in connection with the measurement of large current based on Magneto-Optic Effects. It was used He-Ne laser for light source and was used PIN-Photodiode for light receiver. The sensing section was organized by winding optical fiber around conductor on the concept that the rotation angle of polarizing axis by Faraday Effect is proportional to the applied current in to conduction. The optical signal passed through optical fiber sensor was induced to analyzer arranged in the direction of $\theta$ for input polarization, and then analyzed its rotation angle and researched on operating characteristics of optical CT for 60[Hz] AC current measurement from l00[A] to 1000[A] was carried out. In this results, the output signals induced linearly with the current and proved that the intensity is increased with increasing turns of fiber through output differences which in accordance with turns of fiber and we verified that there is not only difference of the output with the medium between electric field and optical fiber, but also the lineality. Measuring the references and output intensities of the optical CT, ratio errors were within $\pm$7%. This confirmed that error rate will be improved by each medium and turns.

Measurement of High Voltage and Large Current Pulse Using Laser System (레이저를 이용한 펄스형 고전압 및 대전류 측정)

  • Lee, Yoon-Seok;Chang, Yong-Moo;Kim, Jung-Tae;Koo, Ja-Yoon;Kang, Hyung-Boo
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.314-317
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    • 1991
  • The waveforms of high voltage and current pulse were measured using laser measuring systems. Existing potential transformer and current transformer have low measuring precision because of resonance phenomena and waveform distortion due to the magnetic saturation. But using laser measurement, it is possible to obtain clear waveforms which have no effect of distortion and harmonic resonances. And electromagnetic interferences (EMI) in the measuring of high voltage and current pulse, but the optical measuring systems are not subjet to the influence of EMI. Using laser measuring systems based upon Pockels effect and Faraday effect is not free from any errors yet, but it could replace existing measuring systems by routine experiments and error corrections. And it needs that more research and development of optical crystals and equipments would be taken.

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Nonlinear magneto-optic effect based on atomic coherence in Rb D1-line (Rb D1 전이선에서 원자결맞음에 의한 비선형 광자기 효과)

  • Moon, H.S.;Lee, W.K.;An, M.H.;Kim, J.B.
    • Korean Journal of Optics and Photonics
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    • v.16 no.1
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    • pp.7-12
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    • 2005
  • We have observed the nonlinear magneto-optic effect(NMOE) based on atomic coherence in $^{87}$ Rb D$_1$-line using the Rb vapor cell containing 50 Torr of Ne. The width of the NMOE signal was measured to be 2$\pi$${\times}$464 Hz, when the peak-to-peak B-field variation was 1 mGauss. The result of this work may be applied to a high-sensitivity magnetometer.

Output signal characteristic according to temperater change of the optical CT for GIS (GIS용 광CT의 온도변화에 따른 출력특성)

  • Heo, Soon-Young;Ahn, Mi-Kyoung;Jeon, Jea-Il;Park, Won-Zoo;Lee, Kwang-Sik;Kim, Jung-Bae;Kim, Min-Soo
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.2003-2005
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    • 2004
  • 본 논문에서는 패러데이 효과(Faraday effect)를 이용하여 초고압 전력설비에서 대전류 측정을 위한 광CT의 온도변화에 따른 특성에 대한 기초 연구를 하였다. 광원으로는 1310[nm] Laser Diode를 사용하고 수신부로는 PIN-Photodiode를 사용하였다. 실험을 위한 온도변환장치는 GIS와 같은 모양으로 재철은 알루미늄으로서 제작하였다. 광의 전송로는 파이버 내에서 편광상태를 유지할 수 있는 30[m]의 싱글모드 언재킷(unjacked) 파이버를 사용하였다. 전류의 측정은 400[A]에서 1300[A] 까지의 범위에서 측정하였으며 온도는 -40[$^{\circ}$]에서 50[$^{\circ}$]까지 10[$^{\circ}$]씩 증가시키면서 측정하였다. 이 때 출력선호는 인가전류의 중가에 따라 비례하여 증가하였으며 주변온도가 높을수록 비례하여 증가하였다.

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Fiber-optic Ccurrent Sensor Using a Long-period Fiber Grating Inscribed on a High Birefringent Fiber (복굴절이 큰 광섬유에 제작된 장주기 광섬유 격자를 이용한 광섬유 전류 센서)

  • Lee, Yong-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.10
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    • pp.1823-1825
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    • 2007
  • Based on Faraday effect, the variation of current flowing through the conductor can be encoded as that of azimuth angle of light polarization propagating through the fiber coil wound onto the conductor. The amount of current can be obtained by measuring the variation of the light intensity transformed from that of the azimuth angle through a polarization analyzer. In this paper we propose a fiber-optic current sensor system that employs a fiber polarization analyzer as a sensor interrogation device. The fiber polarization analyzer was prepared by inscribing a long-period fiber grating on a high birefringent fiber. At the fixed wavelength of 1522.5 nm, the fabricated fiber device has the polarization extinction ratio of more than 25 dB. The measurement of large current up to 600 Arms was accomplished based on a simple fiber interrogation device and the measurement output of the sensor system showed a good linearity.

Application of a NDI Method Using Magneto-Optical Film for Micro-Cracks

  • Jaekyoo Lim;Lee, Hyoungno;Lee, Jinyi;Tetsuo Shoji
    • Journal of Mechanical Science and Technology
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    • v.16 no.5
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    • pp.591-598
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    • 2002
  • Leakage magnetic flux is occurred in the cracked area of magnetized specimens, and also it changes the magnetic domain area of the magneto-optical film positioned on the specimen. It causes the change of the optical permeability of the magnetic domain on the crack area. So crack images can be obtained easily using this principle. On the other hand, utilizing a laser in this method makes possible to perform a remote sensing by detecting the light intensity contrast between cracked area and normal area. This paper shows the application of non-destructive inspection system taking advantage of magneto-optical method for micro-cracks and presents examples applied to the several types of specimens having fatigue cracks and fabricated cracks using this method. Also the authors prove the possibility of this method as a remote sensing system under the oscillation load considering application to real fields.

A-8 Three -Dimensional Crystalizing Combined $\pi$-Bonding Orbitals ("O" S' Bonding) And Electrical And Mechanical Properties of Alloy Metals

  • Oh, Hung-Kuk
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.03a
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    • pp.90-106
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    • 1995
  • The "O"S' BONDING make metallic and non-metalic crystal structures and form localized superconducting orbitals , which induce electrical conduction , semi-conduction, and superconduction. The orbitals are proced by Ampere's law, Faraday's law , Meissner effect, highcritical temperature of thecopper oxide layers. abnomal trans-membrane signal in cancer cell and plastic deformations bytwins and dislocations, In the case of alloying metals, the most deterimentla cases of electrical conduction are those of solid solution and intermetalic compound . The highest case for the hardness are also those of solid solution and intermetallic compound. It explains the contributions of the "O"S' BONDING for conduction bands and plastic deformation by twins and dislocations.ns and dislocations.

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