• 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.

• 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.

• The korean journal of orthodontics
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• v.14 no.2
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• pp.241-248
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• 1984

The mechanical properties of Cr-Ni alloy of austenitic stainless steel and Co-Cr alloy orthodontic wires were studied in tension. The wires (0.018 inch) were tested in the as-manufactured and heat-treated conditions. Instron type tension testing machine was used for this study. Mean values and standard deviations were computed. The results were as follows; 1. The Cr-Ni orthodontic wires of austenitic stainless steel are generally superior than the Co-Cr orthodontic wires in ultimate tensile strength, In the elongation, however, Co-Cr orthodontic wire are superior than Cr-Ni orthodontic wires. 2. Increase in the degree of strength by heat treatment are more clearly shown in Co-Cr orthodontic wires than Cr-Ni orthodontic wires. And the elongation is decreased by heat treatment in both case. 3. The changes of the degree of strength by cooling method we not clearly shown, but in Cr-Ni orthodontic wires, air cooling are more effective, in Co-Cr orthodontic wires, cooling effect are scarcely shown.

• Journal of Welding and Joining
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• v.19 no.6
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• pp.630-635
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• 2001

The characteristics of spatter generation in the short circuit transfer region of $CO_2$ welding was investigated. Spatteriing phenomena could be classified into three types : Type I generated due to the abrupt increase of arc voltage in arcing duration. Type II by the gas ejection from molten metal and Type III generated by the arc instability at the moment of arc re-ignition just after short circuiting. Main observed types were dependent on the chemical composition of welding wires. The case of YCW12 wires was mainly composed of spatters generated by Type l and Type II, while most, spatters in YCW11 wires were generated by Type II and Type III.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.71-73
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• 2006

AC loss on variation of external magnetic field is a very important factor in development of power applications. In this paper, we measured and compared AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires and uniform-multi-stacked wire made of one type of wires, 1G wires or 2G wires. Measurement was performed using by the linked-picked coil method. As results, as the number of wires increase, AC loss per unit volume of both stacked wires in low external magnetic field is reduced. Also AC loss of 2G slacked wire is higher than that of 1G wire. AC loss per unit length of 2G stacked wire is less than that of 1G stacked wire. And AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires was between uniform-multi-stacked wire made of 1G wires and 2G wires.

• Progress in Superconductivity and Cryogenics
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• v.8 no.2
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• pp.33-36
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• 2006

Multi-stacked HTS wires are needed to conduct large current in the power application. In this paper, magnetization losses of the multi-stacked YBCO wire and the BSCCO wire have been measured and compared. 4 types of YBCO wires and BSCCO wires, that is, single, 2-stacked, 3-stacked and 4-stacked, have been tested. HTS multi-stacked wires were fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various angles of external magnetic field to consider the anisotropic characteristics of HTS wires. The ratios of the magnetization loss by multiple stacking of superconducting wires were presented. Measurements results show that loss reduction ratios have three distinct regions due to the magnitude of external magnetic field, the material of HTS wire and number of stacks.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.220-223
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• 2003

High-Tc superconducting(HT S) systems are commercialized by many study on high-Tc superconductor. For the successful commercialization of superconducting systems using Bi-2223 wires, the database on the degradation of critical current is essentially needed. In this paper, critical current variation of Bi-2223 wires according to the transport time was investigated. The degradation rate of critical current was also calculated. Solenoid type specimens have the length of 190cm Bi-2223 wire and double-pancake type specimens have the length of l0m wire were tested. Tested Bi-2223 wires are commercialized products of AMSC (American Superconductor) and Innost. When the transportation current was 95% of critical current, the degradation of critical current was appeared after 5 hours of transport time.

• Transactions of Materials Processing
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• v.17 no.2
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• pp.91-96
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• 2008

The governing parameters affecting the fatigue properties have been investigated experimentally in the high carbon steel wires with 0.94 wt.%C. In order to find the crucial factors, the advanced analysis techniques such as optical 3-D profiler, focused ion beam(FIB) and transmission electron microscope(TEM) were used. The two-type steel wires with different drawing strain were fabricated. The fatigue properties were measured by hunter rotating beam tester, specially designed for thin-sized steel wires. It was found that the fatigue properties of the steel wires with high drawing strain was higher than that with other wires because of low residual stress and high adhesion condition of brass coating layer.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.42-47
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• 2004

In this paper, we analyzed on the characteristics of the stranded wire disconnected by repeated stress. The stranded wires that were used in the experiment are PVC insulated flexible cords(VCTFK: Vinyl Insulated Vinyl Cabtyre Cord Flat-type) of $0.75mm^2,\;1.25mm^2,\;and\;2.0mm^2$. They are used to connect the load in low voltage. The stranded wires disconnected by repeated stress were magnified with optical microscope. Using X-ray, the disconnected wire were photo-graphed. we compared mechanical characteristics of the stranded wire between disconnected tendency and allowable current. On the mechanical strength of vinyl cap tire ellipse type cords under bending stress, VCTFK of $1.25mm^2$ was the strongest of them. When it was bent $826.3\pm7$ times, it appeared the disconnected tendency that element wires of VCTFK of $1.25mm^2$ are more about 1.67 times than element wires of VCTFK of $0.75mm^2$. In mechanical strength, VCTFK of $1.25mm^2$ is higher about 1.7 times than VCTFK of $0.75mm^2$. Therefore, we found out that mechanical strength was higher, when the wire had a lot of element wires. In comparison with bending stress, VCTFK of $1.25mm^2$ is the strongest among samples, and it is the most useful in wires of movable type.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.90-94
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• 1997

The joints between the superconducting wires are inevitably needed from the requirement of a high magnetic stability with respect to time in the superconducting MRI magnet. In this study, a new superconducting joint using Cu/Nb-Ti sleeve has been tried on the MRI type Nb-Ti superconducting wires. The transformer induction type apparatus was made and applied to measure the joint resistance. A very low joint resistance of 10\ulcorner $\Omega$ could be successfully obtained from this joint method. It was confirmed that the initial rapid current decay occurs before the very stable current decay due to only superconducting joint. Some unstable part in the joint like exposed filaments causes the initial induced current to lower and influence on the increase of the joint resistance.