• Journal of the Korean Society of Industry Convergence
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• v.14 no.1
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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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.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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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.

• Proceedings of the KIEE Conference
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• summer
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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.

• Proceedings of the KIEE Conference
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• 2008.10c
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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.

• Proceedings of the KIEE Conference
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• 1996.07b
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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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• v.18 no.5
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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.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.172-178
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• 2017

Thermal property is one of the important characteristic in the field of energetic materials. As the energy material is released during decomposition, DSC(Differential Scanning Calorimetry) is frequently used for the thermal analysis. In case of the dynamic DSC measurements, thermal dynamic change like melting is prevented from the thermal property measurements. And due to the predicting kg scale, the conditions of the heat exchange with the environment significantly is changed. In this study, As the method to resolve the problem, we predict the thermal aging property using the AKTS thermokinetic program from DSC measurements which performed isothermal method. Predicting the thermal aging properties from ARC(Accelerating Rate Calorimetry) measurement, we compare two results.

• Proceedings of the KIEE Conference
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• 2007.07a
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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.