• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.495-498
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• 2004

In this paper, the arc and flame characteristics of wires were studied during a short-circuit. The short-circuit angle between wires was fixed as $90^{\circ}$ and the experiments were conducted on bare copper wires by varying the diameter of wires. The arc and flame patterns were taken by a high speed imaging system. The direction of arc and flame was explained with Lorentz force. After the short-circuit experiment, the shapes of molten wires were analyzed by a stereo microscope. In the results of experiment, the arc and flame of wires showed particular patterns. The flame characteristics by the diameter of wires were analyzed using a HSIS. We could find out the arc characteristics of wires which were different by the diameter.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.37-40
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• 2015

Recently, the electrical insulation design for electrical apparatuses is important to cope with the tendency of high voltage. The degradation characteristics of a superconducting coil due to an electrical breakdown should be considered to design a high voltage superconducting coil. In this paper, the degradation characteristics of 2G high temperature superconducting (HTS) wires are studied with respect to electrical breakdown tests. To analyze the dependency of the degradation characteristics of 2G HTS wires, the electrical breakdown tests are performed with AC(alternating current) and DC(direct current) voltage. All tests are performed by applying various magnitudes of AC and DC breakdown voltages. To verify the degradation characteristics of 2G HTS wires, the tests are performed with various 2G HTS wires with respect to stabilizer materials. The degradation characteristics of 2G HTS wires, such as Ic(critical current) and index number are measured by performing electrical breakdown tests. It is found that the characteristics such as Ic and index number can be degraded by an electrical breakdown. Moreover, it is concluded that the degradation characteristics of 2G HTS wires are affected by the stabilizer material and applied voltages. The cross-sectional view of 2G HTS wires is observed by using a scanning electron microscope (SEM). As results, it is found that the degradation characteristics of 2G HTS wires are concerned with hardness and electrical conductivity of stabilizer layers.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.680-687
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• 2009

Several kinds of Electrical Wires have been used in Electric Multiple Units(EMU) for the supply of electric power, supervision, and the propagation of control signals. These Electrical Wires must be inspected for safe and stable operation of EMU. The degradation diagnosis to estimate the integrity of Electrical Wires has recently been requested according to the long use of EMU. This paper describes on application of diagnosis method for EMU.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.2
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• pp.1-8
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• 2024

Bonding wires are composed of conductive metals of Au, Ag & Cu with excellent electrical conductivities for transmitting power and signals to wafer chips. Wire metals do not provide electrical insulation, adhesion promoter and corrosion passivation. Adhesion between metal wires is extremely weak, which is responsible for wire cut failures during thermal cycling. Organic coating for electrical insulation does not satisfy bondability and manufacturability, and it is complex to apply very thin organic coating on metal wires. Automotive packages require enhanced reliability of packages under harsh conditions. LED and power packages are susceptible to wire cut failures. Contrary to conventional OCB behaviors, forming gas was not required for free air ball formation for both Ag and Pd-coated Cu wires with Al₂O₃ passivation.

• Fire Science and Engineering
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• v.24 no.4
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• pp.104-108
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• 2010

This paper describes electrical fire on electric pad using carbon type hot wires. A carbon type hot wires electric pad is virtually impossible to connect hot wire as a method of electrical welding or soldering. In order to connect between hot wires, that has to splice carbon type material connector. If junction of hot wires was occurrence of poor connection on electric pad, it increase contact resistance on this junction point. With increasing contact resistance, junction of hot wires on electric pad generates local heating and finally leads to electrical fire. In this paper, we analyzed shape of damage in hot wires caused by electrical local heating and investigated fire cause on electric pad using by carbon type hot wires.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.831-834
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• 2002

Several companies in the world are marketing superconducting wires, films and bulks. High-Tc superconducting systems using these superconductors are begun to commercialize. For the successful realization or commercialization of superconducting system used Bi-2223 wires, the database on the degradation of critical current is essentially needed. In this paper, the electrical degradation of a Bi-2223 wires is measured. The electrical degradation rate was measured after the certain time of continuous current transportation. Specimens have the length of 190cm and double-pancakes coil have the length of 10m were tested. Tested Bi-2223 wires are commercialized product has 115A of Ic. When the transportation current was 95% of Ie, the degradation of Ic was appeared after 5 hours of transportation time. When the transferred current is enough larger than Ic, Bi-2223 double pancake is damaged seriously.

• Transactions on Electrical and Electronic Materials
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• v.10 no.2
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• pp.62-65
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• 2009

YBCO-coated conductors, called "second-generation wires," show a remarkably greater increase in the amount or speed of their resistance than BSCCO wires when a quench occurs. This is probably because of the specific resistance at their stabilizer layer, which also affects their voltage grade. YBCO coated conductors with copper as a stabilizer layer have a voltage grade of 1.5-2 V/cm, and those with stainless steel as a stabilizer layer have a voltage grade of about 0.5-0.6 V/cm. The voltage grade of YBCO coated conductors is important in selecting and applying superconducting wires to power instruments later. In this study, two kinds of YBCO-coated conductors with different stabilizer layers and one kind of BSCCO wire were prepared. Among them, based on the YBCO coated conductors that had a stainless steel stabilizer layer with a low voltage grade, five kinds of experimental samples for joining were prepared with the remaining two kinds of wires. Using the prepared samples, the current application properties and the resistance increase in the flux-flow and the quench states of the single wire and the joined wires were compared.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2094-2096
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• 2005

In this paper, we studied the cross section analysis based on the short circuit conditions of the low voltage bare wires. The copper wires prepared for the experiment were 1.2mm 1.6mm and 2.0mm in diameter. Through the cross section analysis(CSA), it was confirmed that the dendrite structure grew at the angle of about $40^{\circ}$ or $60^{\circ}$ when the fusing current was applied to the wires. The larger the fusing current is, the more decreased the growth angle of the dendrite structure is. It was confirmed that the dendrite structure was arranged like the columnar structure. In this paper, the characteristics analysis of short circuit was carried out in the range of transient duration.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.7-12
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• 2012

This paper describes electrical fire on electric pad caused by defect of hot wires. We analyzed two type electric pad using by carbon type hot wire and magnetic shielded type hot wire. First, a carbon type hot wires electric pad is virtually impossible to connect hot wire as a method of electrical welding or soldering. In order to connect between hot wires, that has to splice carbon type material connector. If junction of hot wires was occurrence of poor connection on electric pad, it increase contact resistance on this junction point. With increasing contact resistance, junction of hot wires on electric pad generates local heating and finally leads to electrical fire. An electric pad using by a magnetic shielded type hot wire happened local heating on signal wire for sensing temperature-rise caused by applying current for magnetic shielded. With increasing local heating of signal wire, insulated coating of hot wire was melted. Finally the magnetic shielded type hot wire electric pad lead to electrical fire with breakdown between signal wire and hot wire. In this paper, we analyzed shape of damage in hot wire caused by electrical local heating and investigated fire cause on electric pad due to defect of hot wires.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.214-214
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• 2009

While critical properties of BSCCO wires rely considerably on grid direction upon BSCCO and have very complicated mechanism of generating a superconducting phase, making it difficult to improve properties of wires, YBCO thin-film wires which can be formed in a superconducting phase upon metal board through vapor deposition processing can get excellent direction and reduce manufacturing costs with more flexibility in improving critical properties; thus, they will be suitable for instrument application in the future. Contrary to BSCCO wires for which thick silver alloy covering materials should inevitably be used, moreover, YBCO thin-film wires have an advantage of making thickness and quality of covering materials different by usage. Such a property can be an important element to widen application of wires by presenting possibility of using thin-film wires as superconducting material for fault current limiter as well as for high power current application. In this study we intend to prepare YBCO thin-film wires with different stabilizer layers to analyze current application and current restriction properties by stabilizer layers on the basis of detailed researches on changes in current classification properties below critical value.