• Title/Summary/Keyword: 와전류 센서

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Detecting Method of Internal Degradation for Cable using Finite Element Method (와전류 센서를 이용한 케이블용 내부 열화 검출 방법)

  • Park, Geon-Ho
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2015.01a
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    • pp.291-292
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    • 2015
  • 와전류 탐상 기법을 이용하여 배전선로의 내부 열화를 검출하는 시스템을 개발할 수 있는데, 본 연구에서는 이를 위하여 유한요소법을 통한 시뮬레이션으로 와전류 센서의 기초 모델링을 구상한 후 실제 와전류 센서를 제작하여 가속 열화에 의한 센서 특성을 조사하였다.

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Design and Characteristics Analysis of Eddy Current Sensor (와전류센서의 설계 및 특성해석)

  • Choi Duck-Su;Lee Hyang-Beom
    • 한국정보통신설비학회:학술대회논문집
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    • 2003.08a
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    • pp.63-65
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    • 2003
  • 본 논문은 수치해석을 이용하여 와전류센서의 설계 및 특성을 고찰하였다. 와전류센서의 설계에 있어서 직경 및 폭을 변화시켰다. 와전류센서에 인가되는 주파수와 lift-off, 도전율의 변화에 대해 수치해석을 수행하였다. 수치해석을 통해 와전류센서의 임피던스값을 산출하고 정규화 임피던스도를 그려 와전류센서의 특성을 살펴 보았다. 수치해석결과, 와전류센서의 폭을 크게 하는 것 보다. 직경을 크게 하는 것이 감도가 좋은 특성을 나타냈다. lift-off효과는 와전류센서와 시험대상 사이의 거리가 작을수록 감도가 좋았다. 도전율 변화에 따른 특성은 도전율이 증가할수록 임피던스도의 반원의 궤적이 아래로 향하는 것을 알 수 있었다.

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Impedance Characteristics Analysis of Eddy Current Testing Sensor for T/R Probe Design (와전류탐상 T/R 프로브 제작을 위한 센서의 임피던스 특성해석)

  • Kim, Ji-Ho;Lee, Hyang-Beom
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.566-569
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    • 2008
  • 와전류탐상(ECT) Transmit-Receive 프로브를 이용한 ECT 방법은 센서코일의 유도기전력의 변화를 관찰하여 피검사체의 결함이나 특성의 변화를 탐지해내는 방법이다. ECT T/R 프로브는 여러 개의 Pancake 코일로 구성되어있고, 각각의 코일은 Transmit 코일과 Receive 코일로 나뉜다. 본 논문은 실제 TH 프로브 제작에 앞서 동일한 특성을 갖는 와전류센서를 설계 및 제작하여 그 특성을 파악하였다. 와전류센서에 인가되는 시험주파수와 Lift-off의 변화에 대한 특성을 파악하고 와전류센서의 임피던스값을 산출하여 정규화 임피던스도를 그려 와전류센서의 특성을 살펴보았다.

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Lift-Off Invariance Transformations for Electromagnetic Eddy Current Nondestructive Evaluation Signals (다양한 센서 측정 거리로부터 획득한 자기적 와전류 신호의 불변 변환 처리 기법)

  • Kim, Dae-Won
    • Journal of the Korean Magnetics Society
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    • v.14 no.6
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    • pp.207-212
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    • 2004
  • Eddy current (EC) testing methods are widely used in a variety of applications including the inspection of steam generator tubes in nuclear power plants, aircraft parts and airframes. A key factor that affects the EC signal is lift-off which means the physical distance between a sensor and a specimen in the testing. In practice, it is difficult to keep track of the actual value of the lift -off during a specific experiment, simulation or testing in the field, which is essential for accurate interpretation of the signal to be used in the following steps. Hence it is necessary to have a scheme to render the EC signal invariant to the effects of lift-off in spite of the changes in the real world. This paper describes a new method for compensating EC signals for variations in lift-off by acquiring an invariance feature using a homomorphic operator and neural network techniques. The signals from various lift-offs are transformed to obtain a zero lift-off equivalent signal that can be subsequently used for defect characterization in the next step.

Application of Eddy Current Sensor for Measurement of TBM Disc Cutter Wear (TBM 디스크커터의 마모량 측정을 위한 와전류센서의 적용 연구)

  • Min-Sung Park;Min-Seok Ju;Jung-Joo Kim;Hoyoung Jeong
    • Tunnel and Underground Space
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    • v.33 no.6
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    • pp.534-546
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    • 2023
  • If the disc cutter is excessively worn or damaged, it becomes incapable of rotating and efficiently cutting rockmass. Therefore, it is important to appropriately manage the replacement cycle of the disc cutter based on its degree of wear. In general, the replacement cycle is determined based on the results of manual inspection. However, the manual measurements has issues related to worker safety and may lead to inaccurate measurement results. For these reasons, some foreign countries are developing the real-time measurement system of disc cutter wear by using different sensors. The ultrasonic sensors, eddy current sensors, magnetic sensors, and others are utilized for measuring the wear amount of disc cutters. In this study, the applicability of eddy current sensors for real-time measurement of wear amount in TBM disc cutters was evaluated. The distance measurement accuracy of the eddy current sensor was assessed through laboratory tests. In particular, the accuracy of eddy-current sensor was evaluated in various environmental conditions within the cutterhead chamber. In addition, the measurement accuracy of the eddy current sensor was validated using a 17-inch disc cutter.

An Experimental Study on a Solenoid Eddy Current Sensor to inspect Deteriorations in Overhead Distribution Lines (가공 배전선의 열화를 검출하기 위한 솔레노이드 와전류 센서의 실험적 연구)

  • 김성덕
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.1
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    • pp.77-85
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    • 1999
  • This paper deals with an experirrental study of a nondestructive testing system using a solenoid eddy currnet sensor to inspect deteriorations in overhead distribution lines, such as broken wires, severe local corrosion or zinc loss. Corrosion rrechanisrn for ACSR and ACSR-OC is discussed and characteristics for a solenoid sensor to insprt the georretrical pararreters of the coil and testing materials impOOance are briefly analyzed. A measurement system having a constant current source, a signal processing unit and a motor driver is impIemented. This instrument has such capabilities as detecting the sensor output and estimating dinHlsions of the testing conductors, continuously. As a result, it was shown that the eddy current sensor with an encircling coil could effectively estimate the diatreter change due to deteriorations in overhead distribution lines. lines.

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Comparison of Eddy Current Testing Probes for Detecting Flaws by Using Finite Element Method (유한요소법을 이용한 결함 진단용 와전류 탐침 코일의 특성 비교)

  • Mun, Ho-Young;Kim, Chang-Eod;Ko, Hyoung-Hwan
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.906-907
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    • 2011
  • 본 논문은 3D 타원형 결함을 가진 알루미늄 판에 대하여 와전류 탐상 프로브 중 Impedance, T/R, T/T 프로브를 설계하여 결함에서의 특성을 파악하였다. 특성 파악을 위해 세 가지의 결함에 대하여 프로브 코일 임피던스의 실수, 허수 변화에 따른 와전류 센서의 특성을 비교하였다.

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Impedance Analysis and Experimental Study of a Solenoid Eddy Current Sensor to Detect the Cross-sectional Area of Non-ferromagnetic Stranded Conductors (비자성 연선도체의 단면적을 검출하기 위한 솔레노이드 와전류 센서의 임피던스 해석 및 실험적 연구)

  • Kim, S.D.;Shim, J.M.
    • Journal of Sensor Science and Technology
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    • v.6 no.2
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    • pp.87-94
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    • 1997
  • Impedance analysis of a Solenoid sensor to detect the cross-sectional area of non-ferromagnetic stranded conductors is described in this paper. To inspect electromagnetic characteristics of conductive materials, a nondestructive test eddy current sensor with an encircling coil is chosen. As solving Maxwell equation, normalized impedance response of the sensor within a conducting rod is modeled and the results are expanded to the stranded wires. Geometrical property affecting on stranded structure is considered and a numerical and experimental study is also presented.

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Designing a Highly Sensitive Eddy Current Sensor for Evaluating Damage on Thermal Barrier Coating (열차폐코팅의 비파괴적 손상 평가를 위한 고감도 와전류 센서 설계)

  • Kim, Jong Min;Lee, Seul-Gi;Kim, Hak Joon;Song, Sung Jin;Seok, Chang Seong;Lee, Yeong-Ze
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.3
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    • pp.202-210
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    • 2016
  • A thermal barrier coating (TBC) has been widely applied to machine components working under high temperature as a thermal insulator owing to its critical financial and safety benefits to the industry. However, the nondestructive evaluation of TBC damage is not easy since sensing of the microscopic change that occurs on the TBC is required during an evaluation. We designed an eddy current probe for evaluating damage on a TBC based on the finite element method (FEM) and validated its performance through an experiment. An FEM analysis predicted the sensitivity of the probe, showing that impedance change increases as the TBC thermally degrades. In addition, the effect of the magnetic shield concentrating magnetic flux density was also observed. Finally, experimental validation showed good agreement with the simulation result.

Application and Design of Eddy Current based on FEM for NDE Inspection of Surface Cracks with Micro Class in Vehicular Parts (자동차부품의 마이크로급 표면크랙 탐상을 위한 FEM 를 기반한 와전류 센서 디자인 및 적용)

  • Im, Kwang-Hee;Lee, Seul-Ki;Kim, Hak-Joon;Song, Sing-Jin;Woo, Yong-Deuk;Na, Sung-Woo;Hwang, Woo-Chae;Lee, Hyung-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.6
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    • pp.529-536
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    • 2015
  • A defect could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size, applied frequency were calculated based on the simulation results. Simulations were carried out for the defect signal of eddy current probe. Exciter and receiver were utilized. In this paper, the FEM simulations were performed in both bobbin-type and pancake-type probe, both probes were optimized under Eddy current FEM simulations and the results of calculation were discussed.