• Title/Summary/Keyword: Static Characteristic

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Firing Circuit analysis of Static Frequency Converter (SFC 시스템의 점호회로 분석)

  • Ryu, Ho-Seon;Shin, Mahn-Su;Kim, Chan-Ki;Lee, Joo-Hyun;Lim, Ick-Hun
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1220-1222
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    • 2003
  • An analysis of thyristor firing and protection circuit applied to SFC(static Frequency Converter) is presented. This consists of firing circuit when thyristor is connected in series, one of overvoltage protection and monitor databack circuit of thyristor states etc. Also, each characteristic of foreign products was studied in this paper.

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Investigation of Excitation System for Nuclear Emergency Diesel Generator (원전 비상디젤발전기 여자시스템 고찰)

  • Shin, Man-Su;Lee, Joo-Hyun;Lim, Ick-Hun;Jeong, Tae-Won
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1894-1895
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    • 2007
  • It is excitation system for nuclear emergency generator that is to startup automatically and sequentially supply essential loads with power. There are static type and alternating exciter, etc in its excitation system. An object of study is static excitation system which power is taken from power potential transformer and power current transformer. It is to complement curtailment of excitation system ability at happening short accidents. And Startup mode are quick startup and slow startup, etc. Its characteristic is looked into in this paper.

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Characteristic Analysis and Static Tests of a Flat Moving Core Type LOA (평판 철심가동형 LOA의 특성해석 및 정특성 시험)

  • Jang, S.M.;Jeong, S.S.;Jeong, J.M.;Kim, H.K.;Wu, J.S.
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.52-54
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    • 1998
  • LOA is the linear electromechanical device that mover is similar to secondary conductor of LIM. The mover reciprocates along stroke by supplying the alternating current to primary coil. LOA is the simpler and more efficient than other linear apparatus using the rotary motor because LOA produce the thrust force without any mechanical converter such as cam, clutch, belt, rack and pinion, etc. This paper deals with the static characteristics of moving coil type LOA by virtual work method, FEM analysis and experiment Results show that thrust force increases when mover travels form center to both ends.

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Static Characteristic of Polyester Fiber by LT-Plasma Polymerization (저온플라즈마중합 처리한 폴리에스터 섬유의 대전특성)

  • 서은덕;강영립;박찬언
    • Textile Coloration and Finishing
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    • v.4 no.4
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    • pp.110-116
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    • 1992
  • For the modification of PET surface, Perfluoropropene and Methyl alcohol were LT-plasma polymerized on the PET fabrics as thin films by means of 13.56 MHz radio frequency generator. The surface properties of PET fabrics were modified from hydrophobic to hydrophilic by application of the postplasma reaction of thin films. The evidence of the modification was identified by observation of the presence of hydroxy group in IR spectrum and the evaluation of degree of hydrophilicity was performed by measuring frictional static voltage of PET fabric with cotton fabric. For the case of modification by PFP, the result performed at the condition of 25 W, 70 m torr has shown to be effective, and for MeOH, result performed at the condition of 25 W, 100 m torr effective. The effect of hydrophilic surface modification of MeOH plasma polymer was superior to that of PFP-plasma polymer.

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Design and Characteristic of the AC Solenoid Valve (AC 솔레노이드 밸브의 설계 및 특성)

  • Kim, Dong-Soo;Jeon, Yong-Sik
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3056-3061
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    • 2007
  • The technology of AC solenoid valves is now considered as a core technology in the fields of the production line of semi-conductor chips and the micro fluid chips for medical applications. And AC solenoid valves, which operate by compressed air, are characterized by high speed response, great repeatability and that the pressure on the cross sectional area of poppet is kept constant regardless of the fluctuation of the pressure exerted on the ports. In this study, AC solenoid valves that posses the high-speed responsibility and the high rate of flow have designed and analyzed through the law of equivalent magnetic circuit and Finite Element Method (FEM) respectively. In case of poppet, Flow field characteristic was analyzed by the variation of poppet and it was able to display flow field by changing the location of the poppet. Also, we verified possibility of the design through the static and dynamic pressure and the 3D distribution curve of the force by working the front poppet.

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Finite Element Analysis of Statics and Natural Characteristic of Vibrating Screen (진동스크린의 정적 및 고유특성 유한요소해석)

  • Hong, Seok-Beom;Kwon, Hyuk-Hong
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.5
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    • pp.886-893
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    • 2013
  • A vibrating screen with multiple decks is widely employed for the process separation of many valuable export commodities. In this study, the inclination angle of the deck of the vibrating screen and the direction angle of the screen's vibration under single particle kinematics were predicted. A finite element model of the vibrating screen was established by parameterization modeling. Through modal analysis and static analysis of the model, the natural frequency, natural vibration mode, and stress distribution of the structure were determined, based on which the dynamics and design optimization of the vibrating screen could be achieved. Future plans also reflect this by conducting detailed design of vibrating screens for the manufacturing plans of vibrating screen machine.

Dynamic fracture catastrophe model of concrete beam under static load

  • Chen, Zhonggou;Fu, Chuanqing;Ling, Yifeng;Jin, Xianyu
    • Computers and Concrete
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    • v.25 no.6
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    • pp.517-523
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    • 2020
  • An experimental system on three point bending notched beams was established to study the fracture process of concrete. In this system, the acoustic emission (AE) was used to build the cumulative generation order (AGO) and dynamically track the process of microcrack evolution in concrete. A grey-cusp catastrophe model was built based on AE parameters. The results show that the concrete beams have significant catastrophe characteristic. The developed grey-cusp catastrophe model, based on AGO, can well describe the catastrophe characteristic of concrete fracture process. This study also provides a theoretical and technical support for the application of AE in concrete fracture prediction.

Combustion Characterisitics of a Catalytic Combustorfor an Automotive Ceramic Gas Turbine (세라믹 가스 터빈용 촉매연소기의 연소특성)

  • Kim, Young-Il
    • Journal of the Korean Society of Industry Convergence
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    • v.1 no.2
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    • pp.49-54
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    • 1998
  • In the catalytic combustor, combustion characteristic and deterioration of catalysts were affected by non-uniformity of pre-mixed gas, Therefore, formation of uniform pre-mixed gas is one of important subjects. In this study, the effect of uniformity and non-uniformity of pre-mixed gas supplied to the catalyst was examined to clarify reaction acceleration and combustion characteristic of the catalytic combustion. It was clarified that static mixer or vaporizer tube length of about 150mm and weak swirl to a combustion air were effictive expedient to make uniform pre-mixed gas. And catalystic inlet temperature needs more than $600^{\circ}C$ with rich pre-mixed gas to active reaction.

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Structural Characteristic Analysis of a Centerless Grinding Machine with Concrete Bed (콘크리트 베드를 이용한 무심연삭기의 구조특성 해석)

  • 김석일;성하경
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.32-36
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    • 2002
  • This paper presents the structural characteristic analysis of a centerless grinding machine with concrete bed. The centerless grinding machine is composed of grinding wheel head, regulating wheel head, concrete bed, wheel dresser and so on. Especially, the concrete bed is introduced to improve the static, dynamic and thermal characteristics of the centerless grinding machine. The structural analysis model of centerless grinding machine is constructed by the finite element method, and the structural characteristics in the design stage are estimated based on the structural deformation and harmonic response under the various testing conditions related to gravity force and directional farces

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A Study on the Optimal Load Shedding Considering Alleviation of the Line Overload (선로과부하해소를 고려한 최적부하간단에 관한 연구)

  • 송길영;이희영
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.6
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    • pp.381-389
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    • 1987
  • This paper presents a method for optimal load shedding in preserving a system security following abnormal condition as well as a sudden major supply outage. The method takes account of static characteristic of generators control and voltage and system frequency characteristic of loads. The optimization problem is solved by a gradient technique to get the maximal effect by the least quantity of load shedding considering line overloads as well as voltage disturbances and system frequency. The method is illustrated on a 8-bus system. It has been found that the use of the proposed algorithm for model systems alleviate the line overload more efficiently than the former method. It is believed that this method will be useful in security studies and operational planning.

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