• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.143-145
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• 1997

특수변압기의 일종인 네온 변압기의 기본원리와 특성을 조사하고 원가절감, 효율향상등 특성개선을 위하여 누설자속의 해석기술과 규소강판의 압연방향에 따른 자속의 영향, 압연방향성 코아의 형상설계방향 등을 제시한다.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.401-409
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• 2015

Defects generated in a railroad track that guides the railroad vehicle have the characteristic of growing fast; as such, the detection technology for railroad track defects is very important because defects can eventually cause mass disasters like derailments. In this study, a speed-up test facility was fabricated to investigate the feasibility of using magnetic flux leakage (MFL) technology for defect detection in a railroad track under speed-up condition; a test was conducted using a railroad track specimen with defects. For this purpose, an MFL sensor head dedicated to the configuration of the railroad was designed and test specimens with artificial defects on their surfaces were manufactured. Using the test facility, a speed-up test ranging from 4km/h to 12km/h was performed and defects including locations were successfully detected from MFL signals induced by defects with enhanced visibility by differentiating raw MFL signals. In the future, it should be possible to apply this system to a high-speed railroad inspection car by improving the lift-off stability that is necessary for speed-up of the developed MFL sensor system.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.111-113
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• 2005

지하에 매설된 가스관의 경우 MFL(Magnetic Fluk Leakage, 자기누설탐상) PIG를 이용하여 금속관의 여러 가지 기계적인 손상을 감지하여 사고예방이나 유지관리의 정보로 활용하고 있다. 이러한 비파피검사는 당장 수리가 필요한 손상에서부터 장래에 위협이 될 수도 있는 지하 매설관 외부의 금속물체(Metal object)까지 찾아낼 수 있어야 한다. 이 논문은 지하 매설관 외부의 금속물체의 크기, 모양 및 이격거리 등에 따른 자기누설 신호를 유한요소법을 이용하여 simulation 하고, MFL PIG를 이용하여 지하 매설관에 대한 비파괴검사를 할 경우 나타나는 여러 가지 자기적 신호를 보정하여 metal object의 크기나 위치 등을 판별할 수 있도록 기본적인 자기누설 정보를 제공하기 위한 연구이다. NMFL PIG의 형상과 금속물체의 크기 종류 의 정확한 분석을 위하여 3차원 해석을 하였다.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.38-40
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• 2005

이 논문은 지하매설관의 손상에 따른 자기누설 신호를 유한요소법을 이용하여 Simulation 하고, 자기누설탐사장치를 이용하여 지하매설관에 대한 비파괴검사를 할 경우 나타나는 여러 가지 자기적 신호를 분석하여 손상의 크기나 형상 등을 판별할 수 있도록 기본적인 자기누설정보를 제공하기 위한 연구이다. 3가지 형태의 결함을 배관과의 상대적인 위치에 따라 3차원 FEM으로 해석을 하고 결함의 형상 및 크기대한 정보제공을 위하여 분석을 하였다.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.75-80
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• 2003

In this paper, we designed add current scan system basically. Although NDT system using AC method in now days had problem with limit of detection rate and limit of device organization, in this paper, we made up these problem so that designed device smaller than system used, reduction of cost of system organization and precision of measuring crack. Also, AC leakage flux system had high accuracy about minute crack in the surface and advantage of designing system easily so that we designed system for concerning about crack of surface. Furthermore, it can be able to detect exact crack of reference in wide area by using DSP320C31 chip to reduce the time of measuring crack.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.268-269
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• 2009

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.707-708
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• 2008

본 논문에서는 초전도 플라이휠 에너지 저장장치 (Superconductor Flywheel Energy Storage System : SFES)의 에너지 변환을 위해 사용된 영구 자석형 전동 발전기(Permanent Magnet Synchronous Motor/Generator : PMSM/G)가 SFES의 에너지 저장효율에 미치는 영향을 평가하였다. SFES 시스템은 YBCO 벌크 초전도체를 이용한 저어널 타입(journal type)의 초전도 베어링을 사용하였으며, 슬롯리스 형 PMSM/G를 사용하였다. PMSM/G의 고정자 코어, 누설 자속 및 감겨진 코일에 의한 저장 에너지 손실을 측정하였다. 사용된 코어의 크기, 누설자속, 및 코일의 적절한 선정을 통하여 저장된 에너지의 손실을 상당히 줄일 수 있음을 확인하였다. 또한 영구자석과 코어가 동시에 회전하는 회전 코어형 전동발전기를 적용하여 에너지 손실을 매우 감소시킬 수 있음을 확인하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.2
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• pp.209-214
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• 1999

New estimation and tuning schemes of inductance variations for rotor flux oriented (RFO) control of induction motor in field weakening region are presented. Stator transient inductance and stator self inductance are estimated. From estimated stator self inductance. magnetizing inductance is estimated and from estimated stator transient inductance, rotor leakage inductance is estimated. Simulation and experimental results prove the effectiveness of the proposed s scheme in constant torque and field weakening region.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.250-254
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• 2001

The resolution of analog sensor is determined by its sensitivity and amplitude of noise. This paper presents modeling of inductive gap sensor base on equivalent magnetic circuit and analysis of sensitivity. We can simulate static characteristic of inductive gap sensor using this model. Computer simulation show that sensor's sensitivity is affected by magnetic flux's leakage and fringing, and that they are affected by shape of sensor probe. Base on this, we designed shape of inductive position sensor probe.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.249-252
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• 1997

The resolution of analog sensor is determined by its sensitivity and amplitude of noise. This paper presents modeling of inductive gap sensor base on equivalent magnetic circuit and analysis of sensitivity. The model of inductive gap sensor is verified by the experimental results. Then we can simulate static characteristic of inductive gap sensor using this model. Computer simulation show that sensor's sensitivity and linearity are affected by magnetic flux's leakage and fringing, and that they are affected by shape of sensor probe.