• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.182-188
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• 2017

An arc eliminator allows a surge current bypass rapidly into the earth to facilitate the circuit breaking process and increase the stability of the load circuit. Thomson coil actuator (TCA) is a type of actuator that can function as an arc eliminator. The TCA has a simple structure and significantly rapid speed compared to the other types of actuators. In this paper, significant variables, which have a dominant effect on the performance of the TCA, are investigated in detail. Using these variables and an optimization algorithm, an optimal design strategy for the TCA is proposed in this research. The efficacy of the proposed optimal design strategy and the feasibility of the application of the designed TCA for a high power circuit breaker as the arc eliminators are validated through the experiment.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.950-952
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• 1998

DC Arc Plasma was applied in order to convert of hydrocabon fuels (Methane) to hydrogen, which has higher available energy. Plasma can generate very high temperatures with a high degree of control, using electricity. Plasma can be used to produce the pure hydrogen fuel, and has rapid response time. In addition, the use of plasma could provide for a greater variety of operating modes including the posibility of virtual elimination of $CO_2$ production by pyrolytic operation and could obtain byproduct (Carbonblack).

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.301-304
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• 2001

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device defends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. In this research, the principle of the interrupting techniques are given and experimental results of hybrid interrupter which is developed by new technology is introduced.

• Laser Solutions
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• v.5 no.3
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• pp.15-20
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• 2002

The principal obstacle to selection of a laser processing method in production is its relatively high equipment cost and the natural unwillingness of production supervision to try something new until it is thoroughly proven. The major objective of this work is focused on the combined features of gas tungsten arc and a low-power cold laser beam. In this work, the laser beam from a 7 watts carbon monoxide laser was combined with electrical discharges from a short-pulsed capacitive discharge GTA welding power supply. When the low power CO laser beam passes through a special composition shielding gas, the CO molecules in the gas absorbs the radiation, and ionizes through a process blown as non-equilibrium, vibration-vibration pumping. The resulting laser-induced plasma(LIP) was positioned between various configurations of electrodes. The high-voltage impulse applied to the electrodes forced rapid electrical breakdown between the electrodes. Electrical discharges between tungsten electrodes and aluminum sheet specimens followed the ionized path provided by LIP. The result was well-focused melted spots.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.564-571
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• 1995

This paper deals with the arc discharge characteristics of kerosene oil as a basic study on electrical discharge machine. Using needle electrode the discharge voltage, discharge current, discharge energy and the shape of discharge crater are measured. In consequence, it becomes clear that the discharge crater(depth, height, diameter) is depending on the discharge energy. Rapid increase in depth, height and diameter of discharge crater was observed during initial discharge, where discharge energy is large. However, rather slow decrease of those values was found when discharge energy is low or N is more than 3. As the ratio of $I_p$$T_on$ increase, the shape of discharge crater gets near circle. The protuberances of the discharge crater were not formed by the melted needle electrode but by the that of work piece.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.919-921
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• 2000

This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device depends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. In this research, the principle of the interrupting techniques are given and experimental results of hybrid interrupter which is developed by new technology is introduced.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.84-89
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• 2013

The demand of LNG tank and the constituting material, i.e., the Al5083 thick plate, increased due to the rapid growth LNG market. To weld the Al5083 thick plate, the gas metal arc welding (GMAW) of high current is necessary to increase manufacturing productivity incurred by the multi pass welding. However, the arc welding vaporizes the volatile element such as magnesium (Mg). This phenomenon changes the Mg composition of the weld metal and the mechanical properties. The study investigated the weldability of Al5083 alloys after conducting high current GMAW. The Al5083 alloy was welded by using different size of welding wires and high current (800-950A). As the arc current increased from 800A to 950A, the mechanical strength decreased and the secondary dendrite arm spacing (SDAS) increased. Even though the arc current increased SDAS, the mechanical strength decreased due to the Mg loss in the weldment. The large diameter of welding wire decreased the dilution of the weld, therefore increasing the Mg content and the strength of the weld. For the reason, the content of Mg in welds was a major parameter to determine the mechanical property for the high current GMAW. For the arc current between 800A and 950A, the yield strength of the weldments showed a relationship with the weight percent of Mg content ($X_{Mg}$): Y.S = 27.9($X_{Mg}$)-11.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.386-391
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• 1999

The charge-discharge, the high-rate dischargeability, and the self discharge characteristics of the electrodes composed of rapidly solidified ZrV\ulcornerMn\ulcornerMo\ulcornerNi\ulcorneralloy, which has the form of partial substitution of Mn, Mo, Ni for V in $ZrV_2$ were studied. The alloys were prepared using Arc & RSP(Rapid Solidification Process) at the rotating roller speed of 2000 and 5000 rpm. Some of them were received heat treatment at$ 560 ^{\circ}C$ for 1 hour after the solidification to investigate the effect of the heat treatment. It was fond that cycle life was significantly improved by RSP, whereas discharge capacity, activation rte and high rate dischargeability were decreased compared with the conventional arc melting method. The capacity loss seems to be due to the loss of the crystallinity and the increase of the cycle life ascribed to the presence of the amporphous phase as well as the refined grain size of less than 0.2$\mu\textrm{m}$. Heat treatment of the alloy cooled at 2000 rpm improved the cycle life. In case of the alloys cooled at 5000 rpm, both the discharge capacity and the activation rate were significantly improved by the heat treatment.

• Journal of Korea Foundry Society
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• v.20 no.5
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• pp.330-335
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• 2000

Functional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported. But a system which can build directly 3D parts of high performance functional material as metal park would get long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we translated the wax patterns to numerous metal tool prototypes by new investment casting process combined conventional investment casting with rapid prototyping & rapid tooling process. With this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P pare to metal part.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1633-1636
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• 2015

Background: The advantages of Rapid Arc plans versus Intensity modulated radiotherapy plans for Carcinoma left breast were analyzed. Materials and Methods: In this study 20 Post mastectomy carcinoma left breast patients were analyzed. Both Intensity modulated Radiotherapy and Rapid Arc plans were generated for these patients. IMRT plans with 7 beams in an arc fashion and VMAT plans with two semi arcs were made to achieve 95% dose coverage to 100% volume. The plans were evaluated using Dose volume Histograms. Results: The mean Conformity and Homogeneity index in VMAT is found to be 1.05 and 0.065 respectively whereas in IMRT it was 1.07 and 0.069. The 20% volume of Heart received a mean dose of 960cGy in VMAT and 1300cGy in IMRT. The mean dose was 1236cGy in VMAT and 1870cGy in IMRT. The ipsilateral Lung received 3395cGy to 5% volume and 1840cGy to 20% volume on an average and the mean dose was 1205cGy in VMAT, while the same were found to be 3525cGy, 2012cGy and 1435cGy respectively in IMRT. The Contralateral Lung received a mean dose of 505cGy in VMAT and 553cGy in IMRT. The mean Monitor units in VMAT were 512MU and 1170MU in IMRT. The NTID in VMAT is $108.8{\times}10^5Gycm^3$ and $110.1{\times}10^5Gycm^3$ in IMRT. Conclusions: The target coverage, homogeneity and Conformity index were better in VMAT plans. The Ipsilateral Lung and heart dose were very less in VMAT plans. The Contralateral Lung dose and the Normal Tissue Integral Dose were also lesser in VMAT plans however the difference is not very appreciable. The MU in VMAT plans is almost 50% that of the IMRT plans which results in the reduction of treatment time. On the whole VMAT proves to be a better modality for treating Ca. Left Breast Patients.