• Tribology and Lubricants
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• 제29권3호
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• pp.143-148
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• 2013

In this study, several sensor parts used to obtain better signal stability are designed, a separate control circuit for the sensor is developed, and the results obtained using this control circuit are analyzed. The capacitances of the whole sensor system are measured using the control circuit connected to an improved flexible printed circuit board and an asymmetric dual sensor coated with a ceramic material. To realize good discrimination for a small change in the measured capacitance as the engine oil deteriorates, a commercial application-specific integrated circuit is installed on the control circuit as a capacitance-to-digital converter. The absolute error of a measured signal is found to be approximately ${\pm}4fF$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2338-2340
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• 1999

In this paper measurements of AE (Acoustic Emission) signals caused by corona discharge were performed to analyze the electrical deterioration in oil. We also examined the relationship between discharge magnitude and peak-to-peak value of AE signals to diagnose the deterioration of liquid dielectrics. From these results, Vpp(peak to peak value) of AE signals was proportional to corona discharge magnitude. The main frequency band of AE signals in oil appeared to 130[kHz].

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.120-129
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• 2002

New method and device for the on-line measurement of soot concentration in a diesel engine oil are proposed, where the measurement principle is based mainly on attenuated internal total reflection. Various laboratory tests of the detector were performed mainly with carbon black particles of different contamination levels. It was found that the proposed detector could be well used to monitor oil deterioration due to soot contamination. Operational range of the detector was found from 0 to 5 mass percentage of soot content. Test results with water and fuel dilution showed that these effects were not remarkable. However, adsorption of carbon black particles to a measurement surface was considered to be a critical problem in the new detector. Effects of particle deposition onto the interface was experimentally evaluated with the oil temperature and turbulence and discussed throughout this work.

• 조명전기설비학회논문지
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• 제14권3호
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• pp.97-106
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• 2000

본 논문에서눈 주상 변압기의 유전정접 측정과 FFT의 이용으로 활선 상태에서 진단할 수 있논 열화 진단 창치를 제안하였다. 본 논문에서 제안한 주상 변압기 열화 진단 장치는 활선 상태에서 절연유위 온도와 유전정점을 측정하며, 진단 결를블 FFT로 처리한다. 진단용 센서에 인가하는 시험 전압은 주상 변압기 2차촉 전압의 0]용으로 외부회 추가 장치 없이도 전단이 가능하다. 또한, 무선 데이터 통선을 이용하여 진단 정보를 지상에서 수신함 으로 주상 변압기의 감사를 별도의 추가 설비 없이 손쉽게 가능하도록 하였다. 시험 전압 가변 실험과 온도 가변 실험을 통하여 제안한 주상 변압기 열화 진단 장치의 유용성을 입증하였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.123-128
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• 2000

The ocean is now increasingly suffering from pollution mainly caused by oil spill accidents roil increasing marine transportation. It cause not only the deterioration of ocean resources but also critical damage on the ocean ecosystem. Present study is an experimental one for the development of the oil skimmer which can collect spilled-oil actively and effectively from the sea surface. As an effort of achieving it, a new type of water wheel attached nil skimmer was devised, based upon the concept of orifice. The shapes of the water wheel, blades and oil storing tank are found to be very important factors on the oil skimming performance through systematic experimental analysis. Real oil recovery test was also carried out in square tank using the oil skimmer with their optimal shapes. Quite satisfactory result are obtained from the test which showed 99% and 98% recovery rates for light oil and heavy oil in still water condition, respectively.

• 센서학회지
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• 제10권4호
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• pp.266-272
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• 2001

자동차 엔진오일의 열화상태를 직접 in situ로 측정할 수 있는 코일형 전기용량 센서를 개발하였다. 엔진 오일팬의 드레인 홀의 제한된 공간 속에서 10 pF 이상을 얻기 위하여 코일형으로 설계 제작되었다. 코일의 직경 및 권선 조건, 포머의 재질 및 구조, 차폐조건 등 안정된 전기용량 측정을 위한 설계 요구 조건을 컴퓨터 시뮬레이션과 실험적인 방법에 의해서 찾아내었다. 제작된 여러 개의 센서를 이용하여 동일한 조건의 사용오일 특성을 분석한 결과 0.25% 이내에서 일치하였다. 차량에 직접 장착하여 장기간 측정한 결과, 심한 진동과 온도 및 습도변화와 전자기적 잡음 등 열악한 차량의 조건에서도 매우 우수한 측정결과를 나타내었다.

• Tribology and Lubricants
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• 제24권1호
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• pp.7-13
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• 2008

In this work, a simple and low cost sensor technique is proposed to test oil color in real time using in-line sensor. It is presented to use a ratio of intensity in red wavelength range to intensities of green and blue wavelength ranges (defined as a 'chromatic ratio') in order to estimate the oil color change. The proposed sensor technique is realized by irradiating a white LED as light source and a RGB color sensor as photoreceiver, and the chromatic ratio of various types of used oils are measured. The results show that chromatic ratio generally reflects chemical deterioration of oil, including oil oxidation and thermal degradation. It is concluded that the proposed sensor could be used for an effective oil monitoring technology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1851-1853
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• 1996

In this paper the criteria for insulating oil condition of pole transformer were suggested by applying the UV-Visible spectrophotometric method. Ageing of insulating oil caused the change in absorbances of oil os well os the deterioration of electrical properties of oil. By comparing the electrical properties such as $tan{\delta}$ and breakdown voltage with the UV-Visible absorbances of oil, criteria for absorbance values determining oil condition were established. This UV-Visible spectrophotometric method might be applied in ageing analysis of oil and be expected to replace the current method.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.129-135
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• 1999

We developed a new measuring equipment which makes it possible to perform on-line measurements with the merits of its implicity and the time-saving characteristics. By using the newly developed measurement system, the amount of aeration is directly measured on several parameters, i.e, engine speed, oil quantity, oil deterioration, oil temperature and viscosity, etc. It showed that oil aeration is strongly related to be gas movements in crankcase and the residence time of circulating oil in oil pan. In addition, in order to clarify the mechanism of aeration and to quantify the degree of aeration, a modelling analysis to predict aeration was performed , and as a guiding parameter, Aeration Index was defined. Finally, the parameter was compared with the actual amount of aeration, and it was confirmed that they gave a good correlation with each other.

• 조명전기설비학회논문지
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• 제14권6호
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• pp.85-92
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• 2000

본 논문에서는 간이 열화 측정 탑촉자를 갖고 무선 데이터 통신의 이용으로 배전용 변압키(주양/지상)을 감사 진단할 수 있는 장치를 개발하였다. 개발한 장치는 크게 건이 열화 측정 탐촉자, 유위 측청 정치, 열화 측정 장치 및 송.수신부(무선 자료 수집 정치, 원격 제여 장치)로 구성되어 았다. 제안한 장치의 효용성 빛 적용성을 검증 하기 위해서 기존의 정밀급 계측 장치와의 비교.분석 실험을 수행하였으며, 그 상관 관계를 검토한 결과, 상대적인 선형 관계가 있음을 확인하였다. 띠라서 본 논문에서 제안한 감시 및 진단 장치를 주상/지상 변압기에 설치하면 간편하면서도 경제적으로 수많은 배전용 변압기의 신뢰성 있는 감시 진단이 가능하리라 기대된다.