• Title/Summary/Keyword: Clamp

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Relationship between the Initial Clamping Force and the Proper Position of Supporter in the Wedge Type Rail Clamp (쐐기형 레일클램프에서 초기압착력과 지지대의 적정위치사이의 관계)

  • Han, Dong-Seop;Lee, Seong-Wook;Han, Geun-Jo;Lee, Kwon-Soon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.357-362
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    • 2006
  • The wedge type rail clamp compresses with small clamping force at first, and with large clamping force when the wind speed increases because of the wedge working. At this time in order to display the wedge working, the rail clamp slips along a rail. If the supporter is not installed in the rail clamp when the wind speed increases more and more, the structure will occur overload which leads the structure to fracture. So the supporter has to be installed in the rail clamp. The proper position of this supporter is determined by the initial clamping force and the wege angle. Therefore in this study we adopted 5-kinds of wedge angle as the design parameters, and carried out the finite element analysis, in order to analyze the relationship between the initial clamping force and the proper position of supporter in the wedge type rail clamp.

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Relationship between the Initial Clamping Force and the Position of Supporter in the Wedge Type Rail Clamp (쐐기형 레일클램프에서 초기압착력과 지지대의 위치사이의 관계)

  • Lee, Seong-Wook;Han, Geun-Jo;Lee, Kwon-Soon;Han, Dong-Seop
    • Journal of Navigation and Port Research
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    • v.31 no.1 s.117
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    • pp.65-70
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    • 2007
  • The wedge type rail clamp compresses with small clamping force at first, and with large clamping force when the wind speed increases bemuse of the wedge working. At this time in order to display the wedge working, the rail clamp slips along a rail. If the supporter is not installed in the rail clamp when the wind speed increases more and more, the structure will occur overload which leads the structure to fracture. So the supporter has to be installed in the rail clamp. The proper position of this supporter is determined by the initial clamping force and the wege angle. Therefore in this study we adopted 5-kinds of wedge angle as the design parameters, and carried out the finite element analysis, in order to analyze the relationship between the initial clamping force and the position of supporter in the wedge type rail clamp.

Development of Climate Change Education Program in High School Based on CLAMP Inquiry of Fossil Leaves (잎화석의 CLAMP 탐구를 통한 고등학교 기후변화 교육 프로그램 개발)

  • Yoon, Mabyong
    • Journal of the Korean Society of Earth Science Education
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    • v.12 no.1
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    • pp.27-39
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    • 2019
  • The purpose of this study is to develop a STEAM program for teaching climate change through CLAMP (Climate-Leaf Analysis Multivariate Program) paleoclimate inquiry in connection with high school 'Integrated Science' subject. In order to do so, we analyzed the 2015 revised national curriculum and science textbook in terms of the PDIE instructional design model, and developed the teaching-learning materials for 10 class hours through expert panel discussion and pilot test. According to the STEAM class procedure, in the situation presentation stage, the fossil leaves were collected from the dicotyledon plants near school, and the LMA (Leaf Margin Analysis) climate inquiry activity. was presented as the learning goal. During the creative design stage, students were taught about geology and leaf fossils in the study region, and CLAMP input data (31 characteristics of morphotype and leaf architectural of fossil leaves) were given. In the emotional experience and new challenge stage, we collected leaf fossils for outdoor learning, explored paleoclimate with CLAMP method, and promoted climatic literacy in the process of discussing tendencies and causes of Cenozoic's climate change. The validity of the development program was assessed (CVI .84) as being suitable for development purpose in all items through the process of establishing reliability among expert panel. In order to apply the program to the high school, a pilot test was conducted to supplement the discrepancies and to review the suitability. The satisfaction rate of the participants was 4.48, and the program was complemented with their opinions. This study will enable high school students to have practical knowledge and reacting volition for climate change, and contribute to fostering students' climate literacy.

A Study on the Wedge Angle of the Rail Clamp according to the Design Wind Speed Criteria Change

  • Lee Jung-Myung;Han Dong-Seop;Han Geun-Jo;Jeon Young-Hwan
    • Journal of Navigation and Port Research
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    • v.29 no.7
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    • pp.641-646
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    • 2005
  • In cargo-working, it unavoidably happens that the quay crane slip along the rail and the container move from side to side. Especially, they involve a lot of risk in bad weather. The rail clamp is a mooring device to prevent that the quay crane slips along the rail due to bad weather or the wind blast while the quay crane do the cargo-working And it will play a greater role in port container terminal integration and automation To design the wedge type rail clamp, it is very important to determine the wedge angle. In this study, we expect that the design wind speed of the quay crane will change over 16m/s. Assuming that the design wind speed is 40m/s, we determined the proper wedge angle of the wedge type rail clamp for the 50ton class quay crane.

Characteristics of a Corona between a Wiring Clamp(Dead End Clamp) and a Porcelain Insulator Used in a 154[kV] Power Receptacle

  • Han, Un-Ki;Kim, Jong-Min;Bang, Sun-Bae;Kim, Han-Sang;Choi, Hyeong-Jun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.9
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    • pp.57-63
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    • 2007
  • The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154[kV] dead end clamp for end users accelerates the occurrence of corona, which in turn leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in 154[kV] power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a UV image camera. A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method(FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.

Active-Clamp AC-DC Converter with Direct Power Conversion (직접전력변환 방식을 이용한 능동 클램프 AC-DC 컨버터)

  • Cho, Yong-Won;Kwon, Bong-Hwan
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.3
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    • pp.230-237
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    • 2012
  • This paper proposes an active-clamp ac-dc converter with direct power conversion that has a simple structure and achieves high efficiency. The proposed converter is derived by integrating the step-down ac chopper and the output-voltage doubler. The proposed converter provides direct ac-dc conversion and dc output voltage without using any full-bridge diode rectifier. The step-down ac chopper using an active-clamp mechanism serves to clamp the voltage spike across the main switches and provides zero-voltage turn-on switching. The resonant-current path formed by the leakage inductance of the transformer and the resonant capacitor of the output-voltage doubler achieves the zero-current turn-off switching of the output diodes. The operation principle of the converter is analyzed and verified. A 500W prototype is implemented to show the performance of the proposed converter. The prototype provides maximum efficiency of 95.1% at the full load.

Creative Design of the Wedge Type Rail Clamp to set the Initial Clamping Force (초기압착력 설정을 위한 쐐기형 레일클램프의 창의적 설계)

  • Han, Dong-Seop;Kim, Yong;Lee, Seong-Wook;Han, Geun-Jo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.3
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    • pp.58-64
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    • 2007
  • The clamping force of a jaw pad is determined by the displacements of main part when two lockers are locked, after the clamping angle of a locker was set up in the wedge type rail clamp for a container crane. In this time, if the resistance of wedge frame generates due to several factors, the clamping angle of a locker to display the initial clamping force will be changed because of the reduction of displacement of extension bar. This resistance is determined by the eccentric distance between the roller and the wedge, and by the gap between the wedge frame and outer frame. In this study we measured the tensile force of both extension bar through the performance test of the prototype rail clamp in order to evaluate the effect of the resistance of wedge frame on the clamping force of the wedge type rail clamp.

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Lab-based Simulation of Carton Clamp Truck Handling - Frictional Characteristics between Corrugated Packages

  • Park, Jong Min;Choi, Sang Il;Kim, Jong Soon;Jung, Hyun Mo
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.25 no.3
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    • pp.131-137
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    • 2019
  • Carton clamps, one of forklift attachments, allow users to quickly handle shipping units such as unitized loads, large shipping cases, or crates without the requirement of pallets. As the use of palletless handling by clamp trucks increases, so does the need for simulation research on clamp truck handling. The frictional characteristics for various contact conditions of corrugated paperboards and their constituent boards were analyzed to obtain the data needed in the computer simulation for the handling of carton clamp truck. The overall mean of static-frictional coefficients between selected corrugated paperboards was 0.38 (±0.01), which was 1.3~1.6 times greater than 0.23~0.29 of the frictional coefficients between boards. The overall mean of static-frictional coefficients between the corrugated paperboards and the rubber contact pad was 0.82 (±0.02), which was about 1.1 to 2.8 times greater than 0.29~0.78 of the static-frictional coefficient between the linerboard and the rubber contact pad. The overall mean of kinetic-frictional coefficients between the corrugated paperboards was 0.35 (±0.01), and 0.76 (±0.02) between the corrugated paperboards and the rubber contact pad.

Characteristic Estimation of Single-Stage Active-Clamp Type High Frequency Resonant Inverter (단일 전력단 능동 클램프형 고주파 공진 인버터의 특성 평가)

  • 원재선;강진욱;김동희
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.2
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    • pp.114-122
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    • 2004
  • This paper presents a novel single-stage active-clamp type high frequency resonant inverter. The proposed topology is integrated full-bridge boost rectifier as power factor corrector and active-clamp type high frequency resonant inverter into a single-stage. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. By adding additional active-clamp circuit to conventional class-E high frequency resonant inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in the fields of induction heating applications, fluorescent lamp and DC-DC converter etc.

Optimal Design of GaN-FET based High Efficiency and High Power Density Boundary Conduction Mode Active Clamp Flyback Converter (GaN-FET 기반의 고효율 및 고전력밀도 경계전류모드 능동 클램프 플라이백 컨버터 최적설계)

  • Lee, Chang-Min;Gu, Hyun-Su;Ji, Sang-Keun;Ryu, Dong-Kyun;Kang, Jeong-Il;Han, Sang-Kyoo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.4
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    • pp.259-267
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    • 2019
  • An active clamp flyback (ACF) converter applies a clamp circuit and circulates the energy of leakage inductance to the input side, thereby achieving a zero-voltage switching (ZVS) operation and greatly reducing switching losses. The switching losses are further reduced by applying a gallium nitride field effect transistor (GaN-FET) with excellent switching characteristics, and ZVS operation can be accomplished under light load with boundary conduction mode (BCM) operation. Optimal design is performed on the basis of loss analysis by selecting magnetization inductance based on BCM operation and a clamp capacitor for loss reduction. Therefore, the size of the reactive element can be reduced through high-frequency operation, and a high-efficiency and high-power-density converter can be achieved. This study proposes an optimal design for a high-efficiency and high-power-density BCM ACF converter based on GaN-FETs and verifies it through experimental results of a 65 W-rated prototype.