• Title, Summary, Keyword: Insulating resistance

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Manufacturing technology of two-layer self bonding insulating tape (이중절연 자기융착테이프 제조기술)

  • 조용석;이철호;심대섭
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.890-893
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    • 2001
  • Two-layer self bonding insulating tape consists of butyl rubber(IIR ; Isobutylene-isoprene rubber) adhesive layer and polyethylene protective film. Butyl rubber have inherent characteristics such as resistance to corrosion and water, low temperature flexibility, excellent electrical insulating properties also resistance to environmental effect such as ozone and ultraviolet. Polyethylene film was used for the purpose of good insulating properties and resistance to ozone and ultraviolet. The tape was manufactured using extrusion and calender method.

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The Analysis of Heat Transfer through the Multi-layered Wall of the Insulating Package

  • Choi, Seung-Jin
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.12 no.1
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    • pp.45-53
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    • 2006
  • Thermal insulation is used in a variety of applications to protect temperature sensitive products from thermal damage. Several factors affect the performance of insulation packages. Among these factors, the thermal resistance of the insulating wall is the most important factor to determine the performance of the insulating package. In many cases, insulating wall consists of multi-layered structure and the heat transfer through this structure is a very complex process. In this study, an one-dimensional mathematical model, which includes all of the heat transfer principles covering conduction, convection and radiation in multi-layered structure, were developed. Based on this model, several heat transfer phenomena occurred in the air space between the layer of the insulating wall were investigated. From the simulation results, it was observed that the heat transfer through the air space between the layer were dominated by conduction and radiation and the low emissivity of the surface of each solid layer of the wall can dramatically increase the thermal resistance of the wall. For practical use, an equation was derived for the calculation of the thermal resistance of a multi-layered wall.

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The Effects of Parka on Subject Wear Sensation as to Thermal Resistance (파카의 보온성에 따른 착용감에 관한 연구)

  • Lee Yoon-Jung;Lee Soon-Won
    • Journal of the Korean Society of Clothing and Textiles
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    • v.13 no.3
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    • pp.295-303
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    • 1989
  • This study is to measure the thermal resistance of 7 types of Parka of different materials with thermal manikin and to compare their effects on physiological responses & subjective wear sensations. Following are the results obtained from the experiments 1) From the thermal manikin experiment, i) As an outer layer, although not significant, water proof fabric was warmer than water proof-vapor permeable fabric. ii) In case of insulating material, down was better for thermal resistance than polyester wadding of the same thickness. Moreover, as the down was thicker, it had more efficiency in thermal resistance. However, the marginal efficiency of thickness was found to be decreasing. 2) From the male-subject experiments, i) Chest temperature, mean skin temperature & microclimate temperature showed the same results on thermal resistance as those of the thermal manikin experiment. ii) Only during rest periods, there was a significant difference among 5 insulating materials in the sense of microclimate humidity. The almost same conclusion was obtained from the above experiments. Even the outer layer did not significantly affect thermal resistance & subjective wear sensation, insulating materials had a significant influence upon them. But in case of 3.5 cm down, it gave less comfortable than that of the thinner. Therefore the optional one for the best comfort & thermal resistance among 7 combinatins is the outer layer of water proff-vapor permeable & insulating material of 2.1 cm down.

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Improvement of the Heat Resistance Reliability of an Axial Smoke Exhaust Fan (배연용 축류팬의 내열 신뢰성 향상)

  • Hur, Jin-Huek;Heo, Ki-Moo;Moon, Seung-Jae;Lee, Jae-Heon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.12
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    • pp.656-662
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    • 2009
  • In this paper, the heat resistance reliability of an axial smoke exhaust fan was investigated. An axial smoke exhaust fan should be capable of operating at $250^{\circ}C$ for 2 hours. The heat resistance reliability was evaluated by the heat resistance reliability test. A B10 life with a 90% confidence level was estimated to be about 48 minute. The failure occurred in the motor due to high temperature. The main failure mechanisms of the motor were melting of bond and insulating paper and burning of insulating materials in the coil. The heat resistance reliability was improved by changing the way to unite the core and the coil and by replacing the insulating paper and the insulating materials of the coil. A B10 life with a 90% confidence level of a modified axial smoke exhaust fan was estimated to be over 120 minute.

A Study on the Partial Discharge Resistance Characteristic for Optimizing the Mixing Ratio of Heterogeneous Inorganic Insulated Materials for Environmentally Friendly GIS Spacer (친환경 GIS Spacer용, 이종 무기물 절연소재의 혼합비 최적화를 위한 부분방전 저항성 특성 연구)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.9
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    • pp.1189-1196
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    • 2018
  • 7 type composites (40, 45, 50, 55, 60, 65, and 70 wt.%)were prepared for the environmentally friendly GIS Spacer. Five kinds of samples were prepared for optimization of the filler content ratio (MS: MA = 1: 9, 3: 7, 5: 5, 7: 3, 9: 1) of epoxy / microsilica and microalumina. As a result of evaluation of the partial discharge resistance characteristic, surface erosion is generally slowed down as the fill amount of micro silica is increased. Also, partial discharge resistance characteristics for the development of insulating materials with optimal mixing ratios of heterologous showed a higher partial resistance of discharge and a decrease in erosion, as the filler content ratio of micro silica was larger. In the future, various researches such as electrical, mechanical, and thermal studies will be needed to develop insulating materials that can commercialize power devices in environmentally friendly insulating gas.

Insulation Properties and Microstructure of SiO$_2$ Film Prepared by rf Magnetron Sputtering (고주파 마그네트론 스퍼터링으로 제조한 SiO$_2$ 절연박막의 구조분석 및 절연저항에 관한 연구)

  • 박태순;이성래
    • Journal of the Korean institute of surface engineering
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    • v.35 no.2
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    • pp.113-121
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    • 2002
  • We have investigated insulating properties of $SiO_2$ interlayer for the thin film strain gauge, which were prepared by RF magnetron sputtering method in various deposition conditions, such as Ar pressure, gas flow rates and sputtering gases. SEM, AFM and FT-IR techniques were used to analyze its structures and composition. As the Ar pressure and the flow rate increased, the insulating interlayer showed low insulating resistance due to its porous structure and defects. Oxygen deficiency in $SiO_2$ was decreased as fabricated by hydrogen reactive sputtering. We could enhance the surface mobility of sputtered adatoms by using Ar/$H_2$ sputtering gas and obtain a good surface roughness and insulating property. The optimum insulating resistance of 9.22 G$\Omega$ was obtained in Ar/30% $H_2$ mixed gas, flow rate 10sccm, and 1mTorr.

A Study on the Damage by Burning Characteristics of Insulating Materials of RCD (누전차단기 절연재료의 소손 특성에 관한 연구)

  • Lee, Chun-Ha;Kim, Shi-Kuk;Ok, Kyung-Jae;Jee, Seung-Wook
    • Fire Science and Engineering
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    • v.23 no.2
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    • pp.62-66
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    • 2009
  • In this study, we study the damage by burning characteristics of insulating material of RCD (Residual Current Device) used in Korea. The insulating materials of RCD manufactured by three manufacturers are used as the sample. We compare and analyze the thermal decomposition characteristics, combustion characteristics and tracking characteristics of samples. The TGA and Mass Loss Calorimeter meeting the requirements for the ISO5660 (Fire tests-Reaction to Fire, part 1) are used for analyzing the thermal decomposition characteristics and combustion characteristics respectively. In addition, the tracking characteristics are analyzed according to standard of KSC IEC 60112 known as the test used for measuring the resistance tracking and comparison tracking indexes. The study results show that the resistance tracking property of insulating material provided by A Company is highest. Also, the test results show that the resistance tracking property of insulating material provided by B Company is lowest. However, the thermal stability of insulating material provided by this company is excellent at high temperature of above $350^{\circ}C$. In addition, the test results show that the thermal stability of insulating material provided by C Company is highest at temperature of below $400^{\circ}C$.

Effect of ceramic powder addition on the insulating properties of polymer layer prepared by dip coating method

  • Kim, S.Y.;Lee, J.B.;Kwon, B.G.;Hong, G.W.
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.1
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    • pp.14-18
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    • 2014
  • The mechanical, electrical and thermal characteristics of insulating materials may significantly affect the performance and reliability of electrical devices using superconductors. General method to provide insulating layer between coated conductors is wrapping coated conductor with Kapton tape. But uniform and compact wrapping without failure or delamination in whole coverage for long length conductor is not a simple task and need careful control. Coating of insulating layer directly on coated conductor is desirable for providing compact insulating layer rather than wrapping insulating layers around conductor. Ceramic added polymer has been widely used as an insulating material for electric machine because of its good electrical insulating properties as well as excellent heat resistance and fairy good mechanical properties. The insulating layer of coated conductor should have high breakdown voltage and possesses suitable mechanical strength and maintain adhesiveness at the cryogenic temperature where it is used and withstand stress from thermal cycling. The insulating and mechanical properties of polymer can be improved by adding functional filler. In this study, insulating layer has been made by adding ceramic particles such as $SiO_2$ to a polymer resin. The size, amount and morphology of added ceramic powder was controlled and their effect on dielectric property of the final composite was measured and discussed for optimum composite fabrication.

A Study on Method of Construction for Foamed Concrete adding EVA Chip that improves the Resistance of Cracking and Capability of Insulating (크랙저항성(抵抗性)과 단열성(斷熱性)을 향상(向上)시킨 EVA칩 첨가 기포콘크리트의 려공법(旅工法) 연구(硏究))

  • Lee, Jong-Shik;An, Jung-Chan;Lee, Jong-Hak
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.5-9
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    • 2007
  • The construction method for Foamed-Concrete has not been important due to following process of construction work. However, according to the code about enhance of energy saving design policy and impact noise, noised isolation has been used in construction site so that the resistance for cracking and capability for insulating of Foamed-Concrete has been required. Therefore, new alternatives are demanded. Optimum mixing design, which can get the improvement of insulation and resistance of crack for Foamed-Concrete adding EVA chip, was derived and also the device, applying to construction site, was invented to equalize quality. This device can measure quantity of all input and placement, and show up the sum of placement and mixing design on a touch screen. This valuable construction method is friendly environment and recycling method because of using EVA chip, by-product of an EVA insole scrap burned or embedded, as a light-weight aggregate.

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Physical and Electrical Characteristics of Varnish and Varnish Treated Insulating Paper for Pole Transformers

  • Jung, Jong-Wook;Song, Il-Keun;Koo, Kyo-Sun;Song, Hyun-Seok;Kwak, Hee-Ro;Han, Yong-Huei
    • KIEE International Transactions on Electrophysics and Applications
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    • v.2C no.6
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    • pp.321-326
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    • 2002
  • This paper describes the mechanical and electrical characteristics of insulating paper impregnated with diluted varnish(W-128), according to Korean Standards. The varnish was diluted with a solvent of 6 different wt%. Kraft paper and Nomex paper were impregnated with the diluted varnish in a vacuum condition, and then completely dried. As the mechanical characteristics, the thickness of the completely dried varnish, the drying time and the tensile strength of the specimens were measured, and as the electrical characteristics, the permittivity, the tan $\delta$ and the specific resistance were evaluated as well.