• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.924-925
• /
• 2011

본 논문에서는 환경친화적이고, 인화점 및 발화점이 높아 화재의 위험도가 낮은 식물성 절연우를 기존 변압기의 광유를 대체로 사용하기 위한 열적 특성을 열유동해석을 이용하여 온도분포를 수치해석을 통하여 예측하였다. 해석모델로는 154kV 급 단상 내철형 유입자냉식 변압기를 대상으로 CFD 해석을 수행하였으며, 광유와 식물성 절연유는 부하의 변화에 따른 온도특성을 파악하는 동시에 핫스팟(hot spot)을 예측하였다. 본 논문은 변압기를 3차원 모델링하여 유동 및 온도 분포를 해석한 결과, 변압기의 내부 온도 및 핫스팟 추적에 대하여 변압기의 수명에 대한 예측이 가능하며, 식물성 절연유를 사용한 전력용 변압기 온도 분포 해석결과는 식물성 절연유의 적용 및 냉각 설계 변경에 기초자료롤 활용될 것이다.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1195-1196
• /
• 2008

최근, 친환경 물질이면서 광유에 비하여 발화점이 높은 식물성절연유에 대한 관심이 고조되고 있으며 식물성절연유변압기의 사용이 미주 등 해외시장에서 급격하게 증가되고 있다. 본 연구에서는 송전급 식물성절연유변압기 개발을 위하여 액체절연 매질의 고전압 시험법을 검토하고 전극 간 이격 거리에 따른 절연파괴 시험을 통하여 식물성절연유의 절연성능을 평가하였다. Weibull 분포와 전계해석을 이용하여 2% 절연파괴전압을 산출하고 전계분포를 계산하여 기존의 변압기 절연매질인 광유와 비교하였다. 본 연구 결과는 향후 식물성 절연유변압기 제작에 필요한 설계 자료로 활용될 것이다.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.9
• /
• pp.723-732
• /
• 2001

In this paper, the neurofuzzy controller of optically guided AGV is proposed to improve the path-tracking performance A differential steered AGV has front-side and rear-side optical sensors, which can identify the guiding path. Due to the discontinuity of measured data in optical sensors, optically guided AGVs break away easily from the guiding path and path-tracking performance is being degraded. Whenever the On/Off signals in the optical sensors are generated discontinuously, the motion errors can be measured and updated. After sensing, the variation of motion errors can be estimated continuously by the dead reckoning method according to left/right wheel angular velocity. We define the estimated contour error as the sum of the measured contour in the sensing error and the estimated variation of contour error after sensing. The neurofuzzy system consists of incorporating fuzzy controller and neural network. The center and width of fuzzy membership functions are adaptively adjusted by back-propagation learning to minimize th estimated contour error. The proposed control system can be compared with the traditional fuzzy control and decision system in their network structure and learning ability. The proposed control strategy is experience through simulated model to check the performance.

• Journal of Energy Engineering
• /
• v.26 no.3
• /
• pp.131-136
• /
• 2017

Automobile engine oil is the most important lubricant for operating as the engine is started. Recently, manufacturers of the automotive industry and lubricants are considerably improving the quality of oil with additive to extend change cycle period. Most customers are recommended genuine oil among different types from shop expert. Through this report we suggest another reference point for consumer to pick highly efficient lubricant. This report is investigated oil compounds to compare with 6 different automotive considering actual running condition for 7 months. we conducted experiment from physical and chemical perspectives. In the field, through various experiments oil compounds between mineral oil and synthetic oil are largely distinguished in oxidation, viscosity, fluid and TBN. These are influenced by engine part wear as piston, bearing etc. Comparing various investigation with different oil the performance of synthetic oil is shown better condition in flash point, oxidation stability and also found less in change pollutant iron, Al compounds. Additives of oil show clear difference Ca level in detergent-dispersant both mineral oil and synthetic oil. And Zn in extreme pressure additives and P in Lubricity improver make no difference to both.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.979-980
• /
• 2013

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1558-1560
• /
• 2004

Liquid-immersed pole transformers have utilized an insulation system consisting of natural cellulose-based materials and mineral oil for many years. If the transformers are installed with the abruptly changing load over limitation, its insulation materials are apt to unexpected aging with high temperature. Therefore we have been conscious of developing a transformer that is more thermally stable then conventional types. To measure temperature distribution in the winding of conventional and newly designed transformers, temperature sensors were installed fordirect reading of oil and conductor temperatures at transformers. And we conducted accelerating aging test for these transformers. The measuring data had made use of the design to hybrid insulation system. Also we could find the possibility of this insulation system to apply in pole mounted transformers.

• Journal of the Korean Chemical Society
• /
• v.21 no.5
• /
• pp.384-388
• /
• 1977

Clay-polymer thickened greases were made by dispersing bentone-polyethylene and bentone-atactic polypropylene into mineral oil at an adequate temperature, and the physical properties such as wear and water washout characteristics, oxidation and shear stabilities, and dropping point of the greases were tested. Even if the greases failed to meet some properties, it was found that those greases can be used for some special purposes, by observing and comparing the properties with those of clay-metallic soap thickened greases that were made in this experiment.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.95-97
• /
• 1997

This paper deals with design and implementation of the controller for optically guided AGV. When AGV has only three photo sensors in front of body, AGV doesn't know how much the entry angle to guide line is. In this case, it is difficult to compensate the tracking error. To make sure that the AGV does not secede the guide line in tracking, PI controller and fuzzy logic controller is proposed. The proposed controller was verified and experienced through real AGV system.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1263-1264
• /
• 2015

본 논문에서는 PDL 기반 인터리빙 가능한 2차 Solc형 광유 간섭 필터를 제안하며, 출력되는 투과 스펙트럼들을 이론적으로 분석 및 실험적으로 측정하였다. 제안된 필터에서 각각의 구성요소는 편광 빔분배기, 반파장판, 그리고 복굴절이 큰 광섬유로 이루어진다. 이전의 Solc형 2차 광섬유 필터에서 복굴절이 큰 광섬유들은 특정한 각도로 융착 결합되어 편광 제어에 한계가 있었지만, 제안된 구조에서는 복굴절이 큰 광섬유 사이 반파장판을 삽입하여 주축의 각도 및 편광 제어를 유연하게 설정하여 출력 투과 스펙트럼들의 스위칭 특성을 유도하였다.

• Journal of Veterinary Clinics
• /
• v.15 no.2
• /
• pp.319-324
• /
• 1998

본 연구의 목적은 개에서 사염화탄소에 의하여 실험적으로 유발된 급성 간장질환에 대 한 침술의 치료효과를 알아보는데 있다. 잡종의 성견 24두를 실험에 사용하였다. 사염화탄소 를 동량의 광유에 회석하고, 24두의 개에 kg당 2 ml을 피하로 주사하였으며, 그리고 6두는 laserpuncture로 치료하였고, 6두는 침으로 치료하였으며, 6두는 전침으로 치료하였고, 6두는 대조군으로서 처치를 안 하였다. 치료는 매일 1회씩 4일동안 실시하였다. 적용된 경혈은 간유 와 영태이었다. 침술의 치료효과는 임상증상, 혈액화학치 및 심전도에 의하여 측정되었다. 치 료후에, laserpuncture군이 다른 군들에 비하여 임상중상, 혈액화학치 및 심전도에 있어서 비 교적 빠른 회복을 나타내었다. 전침 및 침군은 대조군에 비하여 약간 빠른 회복을 나타내었다.