• Journal of the Korean Institute of Gas
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• v.19 no.3
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• pp.49-53
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• 2015

The purpose of this paper is to study and analyze the failure examples for fire by friction on clutch, manual transmission and tire system in a car. In the first example, the driver took the pedal with foot to act the clutch. But the clutch disk did not return from flywheel by leakage of clutch hydraulic line. The heat was produced between clutch disk and flywheel by surface contacting. As a result, it was produced the fire by oil sludge sticked with transmission. In the second example, the transmission system was operated to transfer power of engine by contacting with gear and gear. But, as if the oil of transmission was caused the oil insufficiency because of leaking by crack of transmission case, it found the fact that was produced the fire by deposit material on transmission case. In the third example, when the car's driver continuously pushed an accelerator pedal for escaping from dry pit, the tire took the heat by the friction force between tire and surface of road. As a result, it became the direct cause for the fire. Therefore the driver must manage not to produce the fire with friction parts by heating during running.

• Journal of Korea Foresty Energy
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• v.7 no.1
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• pp.28-36
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• 1987

To know the possibility of fuel substitution for Diesel engine with the seed oil of Evodia daniellii, which is one of the native oil seed trees in Korea. the refined seed oil mixed with light oil in the various rates was tested in the 8 PS Diesel engine: the output, the fuel consumption rate, the governor performance, the rpm stability in the total loading condition. the content of graphite in the burned gas, and the traction coefficients at the different gear stages were maintained The following results were discussed. 1. The output at the normal revolution (2200rpm)was increased as the percent seed oil increased. At the lower rpm (2000-1500rpm )there were no consistent difference in the outputs among fuels of the different percent seed oil 2. The rate of fuel consumption was inclosed as the percent seed oil increased in each loading condition. 3. The more percent sud oil was mixed in the fuel. the better governor performance appeared at both the instantaneous and stable speed. 4. The more percent seed oil was mixed In the fuel, the more stable rpm ratio was maintained 5. The graphite content In the burned gas was increased as the load increased, but there was no apparent difference in the content at each load among the 100$\%$ seed oil, the 100$\%$ light oil, and the mixtures in various rates. 6. In all fuel mixtures the maximam traction coefficent appeared at the third transmission gear stage. Generally in over all transmission gear stages the fuel mixtures of the seed oil:light oil ratio from 7:3 to 5:5 resulted greater traction force than the other fuels.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1686-1693
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• 2014

In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.324-330
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• 2015

When diagnostic ultrasounds are used, an ultrasonic transmission media is used to effectively transmit the ultrasonic energy. Types of ingredients of polymer hydro gel, emulsion, and oil gel were compared with commercialized products by measuring characteristics of ultrasonic transmission media such as skin lubricity, skin moisturizing, and dryness speed which were contained in each different media. The mean friction coefficient measured to investigate skin lubricity showed high in the agent containing a large amount of oil, whereas the mean friction coefficient of the low viscosity emulsion did not show a significant difference with that of the polymer hydro gel. The moisture evaporation measured to investigate the dryness speed of the agent showed highest in polymer hydro gel. This showed that the larger amount of oil it had, the less moisture evaporation occurred. For skin moisture measured to investigate moisturizing characteristics of skin, low viscosity emulsion showed high in moisture content, whereas it showed slowest reduction in moisture content. As a type of emulsion appropriately containing water and oil is superior in skin moisturizing and skin tenderness, it is expected to serve as a dosage form of new ultrasonic transmission media.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.35-40
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• 1997

As demand of electric power are growing and transmission line limited owing to enlargement of the downtown area The eonfidence of underground transmission cable which shows gradual growth are high. It is found whether insulating ability is good or not. In this paper, The exper iment result is shown that the fall of insulating ability and take preventive measure through the analysis of tans, water content, dielectric breakdown voltage, total acid number, volume resistivity , and gas in the oil in an accordance with the characteristic change of oil used very much for insulating oil of cable.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.311-312
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• 2002

Friction losses in complex tribo-technical system are revealed primarily through their effect on the operating temperature level. In order to assess the influence of the oil formulation on the temperature level comprehensive tests were run in a model test apparatus consisting of a special adapter for the 4-ball test rig. More than ten with different formulations (different base oils, additive packages and viscosity modifiers) were tested, The resulting temperature levels varied by nearly 25 %. The objective of this model testing is to assess the influence of the oil formulation on the operating temperature of vehicle manual transmission. The correlation to the real tribotechnical system was confirmed by a VW Polo transmission test.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1107-1113
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• 2015

Test temperature is an important factor affecting the measurement results of dielectric response of field power transformers. In order to better apply the polarization and depolarization current (PDC) to the condition monitoring of oil-paper insulation system in power transformers, the influences and elimination method of test temperature on PDC characteristic spectroscopy (PDC-CS) were investigated. Firstly, the experimental winding sample was measured by PDC method at different test temperatures, then the PDC-CS was obtained from the measurement results and its changing rules were discussed, which show that the PDC-CS appears a horizontal mobility with the rise of temperature. Based on the rules, the “time temperature shift technique” was introduced to eliminate the influence of test temperature. It is shown that the PDC-CS at different test temperatures can be converted to the same reference temperature coincident with each other.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.75-81
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• 1999

In this paper, the details of electronically controlled CVT is described , which Kia Motor company recently developed in prototype form for hybrid passenger car. This transmission has two input shafts, one for engine and the other for traction motor. The shaft for traction motor is located at rear side which is extended from primary pulley shaft and connected to traction motor through adapter gear box. Adopting two input system, various driving mode is available such as motor alone driving in hybrid vehicle application. As far as electrohydraulic system concerned , this transmission uses two bleed type variable force solenoids for line pressure and ratio control, and one on-off solenoid for clutch control. Another feature for this transmission is that oil pump for transmission is separate from CVT for supplying oil pressure even at vehicle standstill.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.265-277
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• 1993

Recently, underground transmission system is growing continuously according to the electric power demand increase in the downtown area. Even if domestic cable makers are manufacturing 154kV oil filled cable and joint, the design technology of cable-joint has not been fully self-reliance. This study is aimed at the detail heat transfer analysis of 154kV cable-joint. So, that is cut into the five sections in order to analyze a conjugate natural convection in two dimensional $r-{\theta}$ coordinate. The streamline and temperature distributions are obtained for each sections. Also the changes of those are analyzed with respect to the variation of transmission currents and cable-joint surface heat transfer coefficients. The same analyses are also shown in view point of the maximum temperature of conductor and local equivalent conductivity.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.577-586
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• 1993

Pesticide protective clothing has not been frequently worn due to its lack of thermal comfort. It is important to develop fabrics which can allow the wearer to work in comfort. One of the possible way to achieve the goal is to produce fabrics with a water- and oil-repellent finish which would resist pesticide penetration but maintain some breathability. The purpose of this study were to evaluate the pesticide barrier properties of untreated and water- and oil-repellent finished nonwoven fabrics. Three types of nonwoven fabrics(Tyvek, Sontara and Kimlon) were used as test specimens. By pad-dry-cure method, each of the specimen was treated with fluorocarbon. The pesticide barrier properties (amount of pesticide penetration and residue) were measured by the gas chromatography. The performance properties of untreated and treated specimens were evaluated with respects to water pepellency(KS K 0590), oil repellency(AATCC 118), water resistance(KS K 0591, AATCC 42), water vapor transmission (KS A 1013) and air permeability(KS K 0570). The results of this study were as follows : 1) The untreated Sontara showed much more amount of pesticide penetration than untreated Tyvek and Kimlon, while the treated Sontara showed little amount of pesticide penetration. 2) After laundering, the amount of pesticide residue in the untreated and treated Sontara was less than that in Tyvek and in Kimlon. 3) Water- and oil-repellent finish improved water repellency, oil repellency, and water resistance of specimens. 4) The untreated Sontara and Kimlon showed higher water vapor transmission and air permeability than untreated Tyvek. Water vapor transmission and air permeability of treated specimen decreased compared to those of untreated.