• Journal of Power System Engineering
• /
• v.10 no.1
• /
• pp.34-40
• /
• 2006

The snow melting system by electric heating wires which is adopted in this study is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow accumulated on it. The system is designed to increase traffic safety and capacity. The electric heating wires are buried under paved road at a certain depth and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, and installation place where the system applies. It is tried to figure out that the appropriate range of required heat capacity and installation depth and intervals for solving snowdrifts and freezing problems with the minimum electric power consumption. The most important factors to design the system are calculation of heating capacity depending on weather condition and depth and interval of the electric heating wires depending on air condition respectively. The study were performed under the range of the air temperatures($-2^{\circ}C,\;-5^{\circ}C,\;-8^{\circ}C$), the intervals of the electric heating wires(70mm, 100mm, 125mm), and the installation depths(50mm, 70mm, 100mm). The ready made commercial program package was used to verify the experimental results.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.254-256
• /
• 2003

AC loss is one of the important superconducting power machine that we have to consider deeply using the stack wires with the HTS. AC magnetic field is occurred around the wires when the electric current is conducted to the stack wires. It also brings electric field to the wires and occurs self field loss, whose quantity is appeared differently by distance of the stack wires. In this paper, transport current losses of a stack short sample of HTS were compared with Norris equation and measured value.

• Progress in Superconductivity and Cryogenics
• /
• v.9 no.1
• /
• pp.57-60
• /
• 2007

Superconducting electric power devices need to stack HTS wires to increase the current carrying capacity. Uniform multi-stacked wires(UMS) which were made of the same HTS wires have been used. This paper shows the magnetization loss of hybrid multi-stacked(HMS) wire made of BSCCO wires and YBCO wires. Five HMS wires, YB(YBCO-BSCCO), YYBB. YBYB, YBBY and BYYB, were made and tested. Magnetization losses of each UMS wire were compared with corresponding HMS wire. Test results show that magnetization losses per unit length of HMS wire are between the corresponding UMS BSCCO wire and HMS YBCO wire below critical magnetic field. Above the critical magnetic field, magnetization losses of HMS wires are larger than that of corresponding both VMS wires.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.44 no.4
• /
• pp.362-369
• /
• 2008

The snow melting system by electric heating wires which is adopted in this research is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow accumulated on it. The electric heating wires are buried under paved road at a certain depth and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, installation place and each country applying the system. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitch for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature($-2^{\circ}C$, $-5^{\circ}C$), the pitches of the electric heating wires(200 mm, 300 mm), heating value($250\;W/m^2$, $300\;W/m^2$, $350\;W/m^2$).

• Advances in materials Research
• /
• v.4 no.3
• /
• pp.165-178
• /
• 2015

Friction coefficient of epoxy metal matrix composites were investigated. The main objective was to increase the friction coefficient through rubber sole sliding against the epoxy floor coating providing appropriate level of resistance. This was to avoid the excessive movement and slip accidents. Epoxy metal matrix composites were reinforced by different copper wire diameters. The epoxy metal matrix composites were experimentally conducted at different conditions namely dry, water and detergent wetted sliding, were the friction coefficient increased as the number of wires increased. When the wires were closer to the sliding surface, the friction coefficient was found to increase. The friction coefficient was found to increase with the increase of the copper wire diameter in epoxy metal matrix composites. This behavior was attributed to the fact that as the diameter and the number of wires increased, the intensity of the electric field, generated from electric static charge increased causing an adhesion increase between the two sliding surfaces. At water wetted sliding conditions, the effect of changing number of wires on friction coefficient was less than the effect of wire diameter. The presence of water and detergent on the sliding surfaces decreased friction coefficient compared to the dry sliding. When the surfaces were detergent wetted, the friction coefficient values were found to be lower than that observed when sliding in water or dry condition.

• Journal of the Korean Society of Safety
• /
• v.23 no.4
• /
• pp.47-52
• /
• 2008

Many researches on fire risk for normal electric wiring have been pursued in advanced countries such as the USA and Japan, but comparative studies of the partial disconnection and normal state of electric wires have not been conducted. Detection system for the cause of partial disconnection is not developed and prevention countermeasure for electrical fire by the cause is not effective. Therefore, in this paper, partial disconnection characteristics on electric wires were derived and analyzed by experiment and electrical-thermal finite element method(Flux 3D) on the model wires which consist of VCTF(PVC insulated PVC sheathed Cap Tyre Flexible Cord, KS C 3304) and IV(lndoorwire PVC, KS C 3302). VCTF is used in wiring portable electric appliances and the IV is used indoors. Interrelationships between partial disconnection premonitory symptom and current were derived and analyzed by the characteristics based on experiments and thermal analysis for electric wire according to current under normal state and 200% overload state of rated current.

• Journal of the Korean Society for Railway
• /
• v.5 no.1
• /
• pp.32-39
• /
• 2002

As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary Wires are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the locations. Corrosion of catenaty wires can make their actual lifetime shorter than that originally designed. Thus, the messenger and ACSR wires, kinds of catenary wire system, were investigated with respect to corrosion, which include new and used ones collected at the field. Tensile strengths and elongations appeared to decrease when the wires were exposed to corrosive environments. The amount of decrease was more prominent as environmental conditions became more corrosive. They are also vibrated with some amplitude everytime pentographs touch contact line. The frequent cyclic load on the wire may result in a fatigue damage. Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 50 to 60% compared with that of new one in average.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1213-1219
• /
• 2008

The deterioration analysis of electric systems in diesel electric locomotives, which were used for over 30 years, was performed to understand current wear and safety information. The electric systems include electric generation, traction motors, control units, high-voltage cables, and wires. In this investigation, various types of performance testing, such as insulation resistance measurement and degradation tests, were conducted to assess the degree of current deterioration. Moreover, an infrared camera was employed to verify abnormal heating in cables and wires. In this paper, the new techniques for evaluation of deterioration in electric systems have been introduced.

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

• Proceedings of the KSR Conference
• /
• 2000.11a
• /
• pp.704-711
• /
• 2000

This study is carried out using a circuit model approach. First, the self and shunt impedances of all the conductors in the rail system and the mutual impedances between different conductors are computed. Then, a circuit representing the both rail systems at interfaces including the rails, feeders, protection wires, contact wires, ground wires is built. Auto-transformers in the system are also represented in the circuit model. The circuit model is then 1]recessed using a circuit solver based on a double-elimination method. Several different scenarios are analyzed, including the load conditions and a few fault conditions with different fault locations. The effect of the buried ground wires is also analyzed by comparing the results with and without the presence of the ground wires. The analysis procedure presented in the paper demonstrated an accurate way of computing fault current distribution and EMC at interfaces between both systems. The results presented in the paper can be used as a reference for estimating interference levels in similar rail systems.