• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1065-1068
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• 2001

Effects of compacting pressure on the electrical and sintering characteristics of Cu25Cr contact material have been investigated. Cu25Cr contact materials were prepared by solid and liquid-phase sintering methods varying compacting pressure. Influence of compacting pressure on electrical characteristics were investigated in the cylindrical stainless-steel vessel using L-C resonant circuit. The physical and electrical properties of solid-phase sintered Cu25Cr material were found to be improved by increased compacting pressure. On the other hand, it was found that compacting pressure had little influence in case of liquid-phase sintered Cu25Cr material. After conditioning, contact resistance of Cu25Cr material was decreased regardless of compacting pressure. With increased compacting pressure, interrupting ability was shown to be increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.146-147
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• 2007

A universal four-point contact measurement method, has an advantage of non-existence of contact resistance, is demonstrated by the experiments with carbon nanotubes and ZnO nanowire. Ti/Au and Pt are tried to compare the influence of contact resistance between two different metals. These metals are selected to make Ohmic contact and Schottky contact originated from their different work functions. For precise experiments, Ti/Au and Pt are separately evaporated to form double 'four-point contact electrodes' on CNTs or ZnO, and the voltage-current characteristics are measured. This method can be applied to universal resistivity measurement for nanotubes and nanowires.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.407-412
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• 2019

In this paper, the changes in the electrical characteristics (arc energy, contact resistance, and bouncing phenomenon) due to the deterioration of the contact are analyzed. The results are generally consistent and can be analyzed for contact deterioration. The results of the experiment demonstrate that the arc energy is linearly related to the current when the contact samples and the voltage conditions are the same. The contact resistance varies due to multiple factors, but is generally within a certain range, and the contact deterioration can be determined. Contact stabilization can be detected by the decrease in the bouncing phenomenon due to deterioration (the change of the shape of the contact).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.6
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• pp.383-388
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• 2014

The relay used is gradually increased. Because it is possible to easily control the high voltage and current. Bounce phenomenon is generated in contact during operation relay. As the result, arc is generated at the contact, thereby shortening the contact lifetime. In this study, we analyzed the bouncing phenomenon due to deterioration. It can be seen from the experimental results, and it is minimized at about 100,000 times. Bouncing phenomenon to increase again after the minimization. Consequently, the bouncing related to contact weight and shape of contact surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.2
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• pp.115-119
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• 2015

The power relay can be easily controlled with high voltage and current through the contacts. For this reason, has become widely used range in a variety of applications. In this study, we measured the contact resistance between the bouncing phenomenon of contact due to the change of load. The results of the experiment, the contact resistance increases with the deterioration of the contact, it is possible to predict the life of the relay contacts through the contact resistance. And relay bounce duration time have occurred in 3.5 ms or less. In addition, it is possible to use the results to design an arc suppression circuit device.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.87-93
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• 2005

In this paper, we analyzed ignition characteristics of combustible material and the waveform of power dissipation, voltage and current by poor contact. And the surface structure of plug by poor contact was analyzed. In the results of experiment, the heat generated by poor contact and ignited the combustible material on power cord sets. The insulation material was molten and carbonized by the heat conduction though plug pit and voids were formed inside of insulation material. The waveform of voltage and power dissipation distorted because of a growth of oxidation by poor contact. In particular, in case that load was big load, the waveform of voltage and power dissipation severely distorted as with the passage of time. The surface of plug pin was changed from erosion mark to welding mark according to big load. The results will be applied to the cause analysis of electrical disaster.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.406-407
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• 2006

This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using the C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}cm^2$ was obtained due to the improved interfacial adhesion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.632-635
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• 2004

The purpose of this paper is to investigate the effect of arc current and contact velocity on the erosion of silver-based contact materials to be used in low voltage circuit breakers. The opening velocity during breaking, which is constant, ranges between 2m/s to 6m/s in the 415V $25kA_{rms}$. Contact erosion is evaluated by measuring the mass change of the cathode and anode. The results show that the increase in opening velocity from 2m/s to 6m/s leads to a decrease in the contact erosion. It is shown that the material transfer from one electrode to another depends on the transfer charge and the opening velocity of the contacts. The contact pairs of AgWC/AgCdO are superior to $AgWC/AgSnO_2In_2O_3$ or AgWC/AgC contact pairs in the contact erosion.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.512-515
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• 2019

Overhead contact systems (OCS) consist of contact and messenger wires, in which the contact wire supplies electric energy to the railway vehicle by contacting a pantograph. However, this mechanical contact is interrupted during frosts or temperatures below $0^{\circ}C$ in the winter. In these conditions, railway vehicle accidents can occur during operation because of the low energy efficiency that results from the increase in the arcing between the contact wire and pantograph. Therefore, the detection of frost or freezing temperatures is necessary to maintain the stable operation of these trains. In this study, we proposed the development of a frost or freezing condition monitoring system on the OCSs that utilizes wireless communication.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.154-159
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• 1995

To achieve a high aspect ration of metal contact, buried contact solar cell scribe the silicon surface using laser. The Q-switched NdLYAG laser which has 1.064$\mu\textrm{m}$ wavelength use for silicon scribing with 25~40$\mu\textrm{m}$ width and 20~200$\mu\textrm{m}$ depth capabilities. The 2~3% shading losses are very low campared to the screen printing solar cell. In this paper, we investigate the silicon scribing theory and pratice, scribing system for BCSC processing.