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실험계획법을 이용한 초고속 스핀들의 언클램핑 (unclamping) 시간 저감에 대한 최적 조건에 관한 연구
정원지(Won-Jee Chung),조영덕(Young-Duk Cho),이춘만(Choon-Man Lee),정동원(Dong-Won Jung),송태진(Tae-Jin Song) 한국생산제조학회 2006 한국생산제조학회지 Vol.15 No.3
By the reason of increased demand of high productivity, the researches on manufacturing process and equipments for reducing cycle time have been made in many directions of a machine tool industries. Especially high productivity is very important to machining center with high-speed spindle. This paper proposed method of reducing T-T(tool to tool) time which results in shorter unclamping time. T-T time varies as factors such as a hydraulic system, a drawbar mass, a flow meter, a disc spring, piston and pipe diameters. In this paper We could find design factors has much influence on decreasing the unclamping time using DOE(Design of Experiment) and optimized the level of the factors using AMESim 4.0<SUP>®</SUP> and visualNastran 4D<SUP>®</SUP>. Finally, we have verified improved result of the optimized factors with initial design.
Development of Simple Simulation by Changing the Stroke of Cylinder for a Oscillation
설상석(Sang-Seok Seol),정원지(Won-Jee Chung),정동원(Dong-Won Jung) Korean Society for Precision Engineering 2016 한국정밀공학회지 Vol.33 No.2
Equipments to influence by external force have to take effect mechanical oscillation. These equipments regardless of the movement on the external force such as roll, pitch and heave etc, worked to keep the height of tote are required for activeness and needed a device as equipment’s fluctuation for rapidly compensation. Because the actual development of these devices is difficult to cost-effectively, we were developed to compensation simulator scaled down 1/50. In this paper, we were studying kinematic characteristics, designed the simulator to grasp the point and manufactured. This paper was analyzed for confirming the superiority of compensation simulator and set up 50 ton crane in practice.
변압기 보호용 비율차동계전기의 고조파 영향에 관한 연구
김경철(Kyung-Chul Kim),황영록(Young-Rok Hwang),고훈(Hun Kho),정동원(Dong-Won Jung),정해성(Hae-Sung Chung),이동욱(Dong-Wook Lee),정채호(Chae-Ho Jeong),이재윤(Jae-Yoon Lee) 한국조명·전기설비학회 2014 조명·전기설비학회논문지 Vol.28 No.6
Power transformers are applied throughout the power system to connect systems of different voltage to one another. Since a ratio differential relay offers high sensitivity in detection of internal faults in power transformers, it is widely used in the main protection system. The use of nonlinear devices such as rectifiers and other devices utilizing solid state switching have been increased in industry during recent years. For nonlinear loads, the load current is not proportional to the instantaneous voltage. This situation creates harmonic distortion on the system. The harmonic could differential relay misoperation if not recognized. This paper aims at analyzing and probing into the influences of harmonics on a ratio differential relay for power transformer protection.
역청탄과 아역청탄 혼합연소조건에서 미분탄 입자크기가 열물성반응과 연소특성에 미치는 영향
성연모(Yon-Mo Sung),문철언(Cheor-Eon Moon),안성율(Seong-Yool Ahn),안재우(Jae-Woo An),정원우(Won-Woo Jung),김승일(Seung-il Kim),정동원(Dong-Won Chung),최경민(Gyung-Min Choi),김덕줄(Duck-Jool Kim) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40
In this study, effect of particle size on combustion characteristics and kinetics in the co-combustion with bituminous and sub-bituminous coals is experimentally investigated using a TGA and a laboratory-scale burner. Characteristic parameters including volatile matter release, ignition, burnout temperature and activation energy are determined from TG and DTG combustion profiles. Distribution of flame length and mean particle temperature is investigated from the slit-burner system. The purpose of this study is to provide fundamental information for developing reaction model in the numerical simulation and to provide operating conditions in blended coals power plants. As coal particle size decreased and volatile matter content increased, characteristic temperatures and activation energy decreased. The ignition, burnout characteristics and activation energy showed a linear effect on particle size and blending ratio. These results indicated that the control of the coal blending ratio can improve the combustion efficiency for sub-bituminous coals and the ignition characteristics for bituminous coals.