• Title/Summary/Keyword: insulation property

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Physical Properties of Calcium Silicate Inorganic Insulation Depending on Curing Time (칼슘실리케이트 무기 단열소재의 양생기간에 따른 물리 특성)

  • Park, Jae-Wan;Chu, Yong-Sik;Jeong, Jae-Hyun
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.6
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    • pp.529-534
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    • 2016
  • Calcium silicate inorganic insulating material is a porous material which is made of 90 wt% of cement. Unlike existing inorganic insulation materials, it is produced without high temperature curing process and also it costs much less than existing inorganic insulation materials. It is an innovative insulation material that supplemented disadvantages of conventional inorganic insulation material. Researches and developments about inorganic insulation materials have been actively researched abroad. Calcium silicate insulation has $0.13g/cm^3$ of specific gravity. Its heat conductivity is under 0.050W/mK, which it similar to conventional inorganic insulation. However, it has weak compressive strength compared to other inorganic insulation. The point of this research is to manifest that calcium silicate inorganic insulating material can have certain compressive strength after curing process with high insulating performance and to find out the proper curing methods and period.

Microstructure Property of High Voyage Motor Stator Insulation (고압전동기 고정자 권선 절연재료의 미세구조 특성)

  • 김희동;주영호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.513-517
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    • 1999
  • High voltage motor(rated 6.6kV and 448kw) has failed in the stator endwinding area during normal service. Experiments on microstructure property were conducted using the control and aged insulations, which were drawn out from stator windings of the high voltage motor. The analyses were characterized using stereozoom microscope(SM), scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy(EDS). SM result shows that large voids are present in the interface between turn insulation and groundwall insulation. SEM results indicated that the groundwall insulation is rarely thermal stress. EDS results showed that chemical elements in the high voltage motor stator insulations were Al, Si, O, K and Fe.

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A Study on Mechanical, Electrical Properties of Epoxy/MICA Composites with MICA Filled Contents (Epoxy/MICA 복합체의 MICA 충진함량 변화에 대한 기계적, 전기적 특성연구)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.2
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    • pp.219-227
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    • 2013
  • This paper reported a study on the thermal, mechanical and electrical insulation properties of epoxy/mica composites. To investigate the effect of mica content, glass transition temperature, mechanical properties such as tensile and flexural strength, and insulation breakdown properties for epoxy composites with various contents of mica. The effect of insulation thickness on insulation breakdown property was also studied. It was observed that tensile and flexural strength decreased with increasing mica content, while elastic modulus increased as the mica content increased. AC insulation breakdown strength for all epoxy/mica composites was higher than that of neat epoxy and that of the system with 20 wt% mica was 14.4% improved. As was expected, insulation breakdown strength at $30^{\circ}C$ was far higher than that at $130^{\circ}C$, and it was also found that insulation breakdown strength was inversely proportion to insulation thickness.

Study of Thermal Conductivity and Mechanical Property of Elastic Epoxy (탄성형 에폭시의 열전도율 및 기계적 특성에 대한 연구)

  • Lee, Kwan-Woo;Lee, Kyoung-Yong;Choi, Yong-Sung;Park, Bok-Ki;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.319-322
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    • 2004
  • In this paper, we studied on the thermal conductivity and a mechanical property of the elastic epoxy. According to industrial development, insulation materials have various properties. They are solid, liquid, gas state, there are various type. Epoxy, a kind of insulation material, demand of not only high hardness but also elastic property. When the electric current flows into the conductor and the place where the heat occurs, this heat becomes the cause which shortens the life of the electrical appliance. Therefore, for the heat occurred transmit quickly, thermal conductivity of the insulation material is highly demanded. We studied on the thermal conductivity of elastic epoxy on the high voltage. In this result, thermal conductivity confirmed that it followed thermal property of mixed epoxy and addictives. Hardness is decreased when addictives increased.

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An Experimental Study on the Property Transformation for High-Heated Inorganic Insulation (고온수열된 무기질단열재의 물성변화에 관한 실험적 연구)

  • 김봉주;김태용;오창희
    • Fire Science and Engineering
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    • v.5 no.1
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    • pp.29-36
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    • 1991
  • The purpose of this study is to understand the variations of the properties of matters according to the heated temperature of inorganic insulation. As a result, form the variation of heat conductivity and maintaining from of insulation, the range of reusable heated temperature of inorganic insulation is as follows. Glass wool : $400^{\circ}C$, Rock wool : $600^{\circ}C$, Perlite : $800^{\circ}C$.

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Effects of SiC Particle Size and Inorganic Binder on Heat Insulation of Fumed Silica-based Heat Insulation Plates

  • Jo, Hye Youn;Oh, Su Jung;Kim, Mi Na;Lim, Hyung Mi;Lee, Seung-Ho
    • Journal of the Korean Ceramic Society
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    • v.53 no.4
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    • pp.386-392
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    • 2016
  • Heat insulation plates of fumed silica were prepared by mixing fumed silica, SiC powder and chopped glass fiber by a high speed mixer followed by pressing of the mixture powder in a stainless steel mold of $100{\times}100mm$. Composition of the plates, particle size of SiC, and type of inorganic binder were varied for observation of their contribution to heat insulation of the plate. The plate was installed on the upper portion of an electric furnace the inside temperature of which was maintained at $400^{\circ}C$ and $600^{\circ}C$, for investigation of heat transfer through the plate from inside of the electric furnace to outside atmosphere. Surface temperatures were measured in real time using a thermographic camera. The particle size of SiC was varied in the range of $1.3{\sim}17.5{\mu}m$ and the insulation was found to be most excellent when SiC of $2.2{\mu}m$ was incorporated. When the size of SiC was smaller or larger than $2.2{\mu}m$, the heat insulation effect was decreased. Inorganic binders of alkali silicate and phosphate were tested and the phosphate was found to maintain the heat insulation property while increasing mechanical properties.

A Study on the Physical Properties of Mineral Hydrate Insulation Material Mixed with Basalt Fiber

  • Park, Jae-Wan;Chu, Yong-Sik;Seo, Sung-Kwan;Jeong, Jae-Hyen
    • Journal of the Korean Ceramic Society
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    • v.53 no.1
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    • pp.63-67
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    • 2016
  • Mineral hydrate is a new insulation material that compensates for the defects of existing materials. Mineral hydrate is made of inorganic ingredients; therefore, it is nonflammable. The porous structure of mineral hydrate makes the material lightweight and insulating. Mineral hydrate insulation and similar products have been studied and manufactured in Korea and abroad. However, these insulation materials need to improve in terms of strength. In this study, basalt fiber was used to enhance the strength. In order to observe the property changes, compressive strength, heat conductivity, and specific gravity were measured and XRD pattern analysis was performed. These tests confirmed that basalt fiber was effective at improving the strength and lowering the heat conductivity of mineral hydrate insulation.

Electrical AC Insulation Breakdown Characteristics of Various Epoxy / Heterogeneous Inorganic Mixed Composite (여러 종류의 에폭시/이종무기물 혼합 콤포지트의 전기적 교류 절연파괴 특성)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.11
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    • pp.1463-1470
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    • 2018
  • In this study, 20 types of samples were prepared by mixing different kinds of inorganic materials to develop insulation materials for epoxy - based GIS substation equipment used under high voltage environmentally friendly insulation gas. One of the electrical characteristics, AC insulation breakdown experiment was performed. As mixing ratio of mixed heterogeneous inorganic materials, the dielectric breakdown strength was increased with increasing filler ratio of micro silica, micro silica : micro Alumina, 1:9, 3:7, 5:5, 7:3, 9:1, and decreased as the filling amount of micro alumina increased. The AC insulation breakdown characteristics were the best when the composition ratio was 9:1. The higher the content of silica, the better the interfacial properties, and the larger the alumina content ratio, the worse the interfacial properties.

Thermal Property Characteristics of Super insulation Vacuum Panel (초진공 단열재의 열 물성 특성에 관한 연구)

  • Jeon, Hyun-Seok;Choi, Hyoun-Jung;Choi, Gyoung-Seok;Kang, Jae-Sik;Lee, Seung-Eon
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.599-602
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    • 2009
  • Recently, some major environmental problems are the increase of fossil fuel price and $CO_2$ emission. To solve these problems, it is imperative to develop eco-friendly techniques and to reduce energy consumption in apartment complexes. Therefore, an effective system for insulation needs to be developed to reduce energy consumption. This study compares thermal characteristics between general insulation and super insulation Vacuum Panel, which is thinner and has more insulation efficiency.

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A Study on Insulation Property of VPI Type Generator Stator Winding Through the Case Analysis of Insulation Breakdown (절연파괴 사례분석을 통한 진공함침 방식 발전기 고정자권선의 절연특성 연구)

  • Kong, Tae-Sik
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.3
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    • pp.311-316
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    • 2010
  • According to increase of combined cycle power generation, the manufacturing market of gas turbine generator has become more competitive, so there is high pressure on the manufacturer to reduce generator price. Global VPI(vacuum pressure impregnation) method is effective to save the production cost and time for manufacturing stator windings, but it has an abrasion problem by vibration between stator windings and slots. This paper presents the insulation breakdown case, which is for VPI type generator during high voltage insulation tests, and also shows the cause analysis, repair works as well as reliability test. the purpose of this paper is to understand the insulation properties of VPI type generator and to know prevention of insulation weakness.