• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.502-507
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• 1999

An improved, accurate and reliable high-voltage measuring system utilizing a bushing-type capacitor is proposed in this study. This system measures voltages and phase angles of three-phase 22.9 kV power distribution lines and provides enough current to charge a battery for a motor-driven load switch and to operate the measuring and communication circuits for the distribution automation. For reliability, epoxy resin was used as the dielectric material of the bushing-type capacitor since the dielectric strength of epoxy resin is very stable over the wide range of temperature. Capacitances were investigated and found to be stable over the wide range of temperature and applied voltage, and the results indicate that the proposed measurement system is very reliable.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.91-96
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• 2012

The surface of bushing is contaminated with rain, dust, salt and others. A bushing with contaminations in air is serious problem in insulation. Therefore, it is important to understand the inspection and diagnoses of the safety. The ultra-violet rays(UV) camera has attracted interest from the view point of easy judgement. In this paper, we will report on the corona discharge characteristics of surface flashover model with contaminations in air. Also, UV images of discharge and corona pulse count in air are analyzed using prototype UV camera of Korea and a UV sensor with an optic lens. These results are studied at both AC and DC voltage under a non-uniform field.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.88-97
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• 1998

Compliance elements such as bushings of a suspension system play a crucial role in determining the ride and handling characteristics of the vehicle. In this paper, a general procedure is proposed for the optimum design of compliance elements to meet various design targets. Based on the assumption that the displacements of elastokinematic behavior of a suspension system under external forces are very small, linearized elastokinematic equations in terms of infinitesimal displacements and joint reaction forces are derived. Directly differentiating the linear elastokinematic equations with respect to design variables associated with bushing stiffness, sensitivity equations are obtained. The design process for determining the bushing stiffness using sensitivity analysis and optimization technique is demonstrated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.217-218
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• 2005

절연지는 콘덴서 뿐만 아니라 변압기 및 부싱, 전력 및 전화케이블의 절연을 위해 전기분야에서 폭넓게 사용되고 있다. 각 응용 분야에 따라서는 전기적, 기계적 특성이 달리 요구되므로 절연지의 준비단계나 펄프의 처리단계에서 서로 다른 방법으로 만들어진다. 본 내용은 절연지의 절연파괴 강도와 유전체 손실에 영향을 미치는 것들에 대한 발전된 기술을 소개하기 위한 것이다. 절연지의 전기적 특성을 고찰한다는 것은 절연지가 거의 항상 절연유와 함침된 상태로 사용되기 때문에 매우 어렵다. 왜냐하면 함침에 사용된 절연유의 증류에 따라 조합된 절연유와 절연지의 전기적 특성에 대단히 중요한 영향을 미치기 때문이다. 본 내용에 소개된 결과들은 전기 절연과 관련된 절연지의 주요 물리적 특성을 관찰하기 위하여, OF 케이블에 사용된 한가지 특수한 저점도유를 사용해서 얻은 것이다. 또 본 내용은 절연지의 주요 열적, 기계적 특성과 절연유의 주요 특성이 기술되어 있다.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.9
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• pp.117-122
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• 1999

Track rubber parts has heat built-up as long as dynamic loading is applied from running tracked vehicles. Durability is required for rubber part to sustain the heat accumulation and heat exchange between rubber-metal assembly and environmental air and ground. For this research, the track assembly was divided into four parts i.e., bottom track shoe, upper track pad, pin busing and metal structure. Three rubber parts and metal structure were modelled and analyzed with MARC package program to obtain time-temperature data which was induced form mechanical work of tracked vehicles. heat accumulation data was obtained from special experiments under the room temperature of 25$^{\circ}C\;and\;35^{\circ}C$ to simulate the actual environmental conditions. From this research, it is cleared that the environmental temperature does not affect to the heat accumulation speed in rubber parts. Also, the heat built-up mechanism was clarified from the thermo-mechanical work based on numerical analysis and experiments.

• Progress in Superconductivity and Cryogenics
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• v.10 no.3
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• pp.32-35
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• 2008

A common problem in many fields of cryogenic power engineering is applying high voltage to cold parts of superconducting apparatus. In many cases, a bushing provides electrical insulation for the conductor which makes the transition from ambient temperature to the cold environment. The 60 kV class cryogenic high voltage bushing for neutral line of the 154 kV / 100MVA high temperature superconducting (HTS) transformer was described. The bushing is energized with the line-to-ground voltage between the coaxial center and outer surrounding conductors; in the axial direction, there was a temperature difference from ambient to about 77 K. For the insulation design of cryogenic bushing, electrical insulation characteristics of the GFRP were discussed in this paper.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.35-41
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• 2006

In this study, we presented the problems in the insulation cover of 22.9kV transformer bushing through investigating actual conditions. After thermal stress applied to the insulation cover, deterioration patterns, thermogravimetric and infrared characteristics were analyzed, and the results were applied to the cause analysis of accidents and judgement of safety. The insulation covers are used to protect exposed terminals of transformer, but they had improper size and length. Therefore, they could not show efficient insulation function. In case that thermal stress of $150^{\circ}C$ was applied to the insulation covers, plastic insulation covers(A, B, D, E) damaged severely, whereas rubber insulation cover(C) showed normal shapes. In the result of thermogravimetric analysis, the thermal gravity of plastic covers(A) decreased about 33.3% at $307.8^{\circ}C\;to\;405.9^{\circ}C$. and he thermal gravity of rubber covers (C) decreased about 53.7% at $258.8^{\circ}C\;to\;32.9^{\circ}C$. In the result of FT-IR analysis, plastic covers showed peaks characteristic of $CH_2,\;CH_3$, C=O and C=C bonds, whereas rubber covers showed peaks characteristic of OH, $CH_2,\;CH_3$, C=O, C=N and C=C bonds.

• Tribology and Lubricants
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• v.23 no.6
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• pp.306-311
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• 2007

This paper presents the friction characteristics of pb-fres pin bushing bearings for an automotive gasoline engine. The external load is 100 N to 600 N and the speed of the pin bushing bearing is 1000 rpm to 3000 rpm against the rubbing surfaces. And the contact modes of rubbing surfaces between a piston pin and a pb-free pin bushing specimen are a dry friction, an oil lubricated friction and a mixed friction that is starved by a lack of engine oil. Two influential factors of a contact rubbing modes and a material property are very important parameters on the tribological performance of a friction characteristic between a piston pin and a pb-free pin bushing. The experimental result shows that the pin bushing speed of 2000 rpm shows a typical oil film lubricated sliding contact mode in which means that as the applied load is increased, the friction loss is increasing. But other contact mode depending on the speed and the load may affect to the fiction coefficient without a regular and uniform trend. In summary, the oil lubricated rubbing surface definitely decreases a running-in period in short and increase oil film stiffness, and this may leads the reduction of a friction loss.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.996-1001
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• 2011

A bushing is very important because it must supply the high voltage to the power equipment. Generally, the surface of bushing is contaminated with rain, dust, salt and others. A bushing with contaminations at air are serious problem in insulation. Therefore, it is important to understand the inspection and diagnoses of the safety. The ultra-violet rays(UV) camera has attracted interest from the view point of easy judgement. In this paper, we will report on the corona discharge characteristics on bushing model with contaminations. Also, UV images of discharge in air are analyzed using prototype UV camera of Korea. These results are studied at both AC and DC voltage under a non-uniform field.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.34-39
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• 1998

In order to compute the forces which are transmitted through rubber bushings with a commercial multibody dynamic analysis (MBDA) program, a rubber bushing model is needed. The rubber bushing model of MBDA programs such as DADS or ADAMS is the Voigt model which is simply a parallel spring-viscous damper system, meaning that the damping force of the Voigt model is proportional to the frequency. However, experiments do not necessarily support this proportionality. Alternatively, the viscoelastic characteristics of rubber bushings can be better represented by the complex stiffness. The purpose of this paper is to develop a viscoelastic rubber bushing model for the MBDA programs. Firstly, a methodology is proposed to calculate the complex stiffness of rubber bushings considering static and dynamic load conditions. Secondly, a viscoelastic rubber bushing model developed which uses standard elements provided by DADS. The proposed methods are applied to the rubber bushings of the lower control arms of a rear suspension of a 1994 Ford Taurus model. Then, the forces computed for the rubber bushing model are analyzed and compared with the Voigt model in time and frequency domains.