• 한국산업융합학회 논문집
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• 제14권1호
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• pp.15-21
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• 2011

Welding variables and conditions in gas metal arc welding (GMAW) effect on the quality and productivity of the weld, extensive research efforts have been made to analyze the effect of the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the characteristics of the power supply, wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.565-568
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• 2002

Welding variables and conditions in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the characteristic equations of the power supply, wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated, seam tracking procedure using arc sensor was simulated with variable V-Groove geometries and weaving frequencies. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

• 한국산업융합학회 논문집
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• 제4권2호
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• pp.207-213
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• 2001

Welding variables and condition in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the chararcteristic equations of the power supply. wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.788-790
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• 2004

This paper describes the phenomenon of the molten metal bridge theory of the arc discharge at opening contacts. And we analyze the magnetic force and drag force acting on the arc column in the DC magnetic contactor Arc cooling time by the force convection is calculated in the thermal dynamic equation using mean temperature method. Since arc gas lost conduction characteristics below a such temperature, it verify that the process of forming and extinguishing arc is able to analyze in terms of temperature characteristic by simulation and experiments of the 3 types arc extinction unit. It propose the practical simulation method to improve the electrical endurance of dc contactor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.90-92
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• 2008

A novel solving technique has been developed to analyze the dynamic characteristics of high speed Thomson-coil arc eliminator. The electromagnetic repulsion actuator based on Thomson-coil is taken as the driving part of the arc eliminator, due to which, the opening and closing time is quite short compare to other type actuators. The electromagnetic repulsion actuator is composed of one repulsion plate and two fixed coils, corresponding to the opening coil and closing coil, respectively. The new solving technique is derived based on the equivalent electric circuit model of the system which is set up by dividing the repulsion plate into multi segments using adaptive segmentation method. This solving technique is applied to the dynamic characteristic analysis of electromagnetic repulsion actuators in high speed Thomson-coil arc eliminators. The calculation results are testified by the FEM calculation results and experiment results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.850-852
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• 1996

High impedance fault (HIF) is defined as fault that general overcurrent relay can't detect or interrupt, Especially when HIF occur under 15 kV, energized high voltage conductor results in fire hazard, equipment damage or personal threat. Because most HIF occur arc, HIF detection using arc is to increase. Numerical arc model can be applied in an electromagnetic transients program (EMTP) to reproduce the dynamic and random characteristic of arcs for any insulator arrangement, current and system voltage. It allows the representation of any network configuration to be investigated, so the digital simulation of arc faults through air can be substitute for demanding power arc test.

• Journal of Welding and Joining
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• 제18권5호
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• pp.41-48
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• 2000

Dynamic behaviors of the GMAW system are simulated using the short-circuit transfer model and the characteristic equations fir the power supply, wire system and arc. The conventional wire equation, which relates the rate change of the wire extension to the wire feed rate and melting rate, is modified to include effects of the molten drop attached at the wire tip. The modified wire equation describes behaviors of the GMAW system more precisely and provides information about the initial bridge volume for short-circuit transfer. The proposed short-circuit model predicts the variation of parameters such as the current, voltage, short-circuit frequency and time considering the effects of the surface tension and electromagnetic force due to current. The calculated results are in broad agreements with the experimental results under the argon shielding condition.

• 전기학회논문지P
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• 제58권4호
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• pp.427-431
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• 2009

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated from an electrical response point of view. To analysis power line disturbance by induced contact loss phenomenon for high speed operation, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that an arc phenomenon by loss of contact brings out EMI. In case of a high-speed train using electrical power, as comparison with diesel rolling stock, PLD(Power Line Disturbance) such as harmonic, transient voltage and current, EMI(Electromagnetic Interference), dummy signal injection etc usually occurs. Throughout experiment, it is verified that an arc phenomenon is brought out for simulator operation and consequently conducted noise is flowed in electric circuit by power line disturbance.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.172-178
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• 2017

열적 특성은 에너지 물질 분야에서 중요한 특성 중 하나로, 에너지 물질 분해 시 분해열을 방출하기 때문에 DSC(시차 주사 열량계, Differential Scanning Calorimetry)를 자주 사용하고 있다. 승온속도를 달리한 DSC 측정의 경우, 용융과 같은 열역학적 변화로 인해 물질의 열적 측정에 방해를 준다. 또한 kg 단위로 예측하기 때문에 mg 단위 때와는 다른 공간상의 열 변화의 변수가 생긴다. 이번 연구에서는 이 문제점을 해결하는 방안으로, 등온 조건으로 한 DSC(Differential Scanning Calorimetry) 기초 데이터로 ATKS thermokinetic 프로그램을 이용하여 열적 노화 특성을 예측한다. 그리고 g 단위로 측정하는 ARC(Accelerating Rate Calorimetry)의 데이터를 이용하여 열적 노화 특성을 예측하고 결과를 비교 할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1155-1156
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• 2007

This paper deals with dynamic simulation and design characteristic of Linear Switched Reluctance Motor (LSRM). First, we derived design factor from pole arc ratio of stator and mover. Second, we decided design parameter from design factor using time constant. Finally, analyze dynamic characteristics for LSRM using simulation.