• Title/Summary/Keyword: tan ${\delta}$

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Modulus and Fractural Side Measurement of Semiconductive Shield (Materials) in Power Cable Using the DMA (DMA를 사용한 전력케이블 내 반도전층 재료의 탄성율 및 에너지 손실 측정)

  • Yang, Jong-Seok;Lee, Kyung-Yong;Choi, Yong-Sung;Nam, Jong-Chul;Park, Dong-Ha;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.213-214
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    • 2005
  • To measure modulus and damping of semiconductive materials in power cable, we have investigated the modulus and damping of semiconductive materials showed by changing the content of carbon black. Then they were produced as sheets after pressing for 20 minutes at 180[$^{\circ}C$] with a pressure of 200[$kg/cm^2$]. The content of conduct ive carbon black was the vailable, and their contents were 20, 30 and 40[wt%], respectively. The modulus and $Tan\delta$ experiments were measured by DMA 2980. Ranges of measurement temperature from -50[$^{\circ}C$] to 100[$^{\circ}C$] and measurement frequency is 1[Hz]. The modulus of specimens was increased according to a increment of a carbon black content. And modulus was rapidly decreased at the glass transition temperature. The $Tan\delta$ of specimens was decreased according to a increment of a carbon black content.

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Characteristics of Dissipation Factor in Large Generator Stator Bars (대용량 발전기 고정자 바의 유전정접 특성)

  • Kim, Hee-Dong;Kong, Tae-Sik;Ju, Young-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.402-403
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    • 2009
  • Accelerated aging tests were conducted under laboratory conditions on two generator stator bars. Electrical stress is applied in No. 1 model stator bar. Electrical and thermal stresses are applied in No. 2 model stator bar. As aging times increased from 0 to 11460h, dissipation factor($tan{\delta}$) test was performed on No. 1 and No.2 model stator bars. The ${\Delta}tan{\delta}$ of No. 1 and No. 2 stator bars increased with increased in aging time.

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A Study of Dynamic Viscoelastic Properties on Temperatures of Natural Rubber (천연고무의 온도에 따른 동적 점탄성 연구)

  • Lee, Bum-Chul;Yoo, Kil-Sang
    • Elastomers and Composites
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    • v.32 no.1
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    • pp.29-36
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    • 1997
  • The change of elastic modulus(E'), loss modulus(E"), and loss $tangent(tan{\delta})$ were investigated on condition of double strain amplitude (DSA) at temperature of $-40{\sim}80^{\circ}C$ for carbon black filled natural rubber. E', E", and $tan{\delta}$ were increased as it closed to the glass transition temperature due to decrease of rubber network flexibility and carbon black agglomerate interaction. In the micro strain range, energy loss showed maximum value because of the chain slippage in rubber matrix, but the regeneration of carbon black agglomerate and rubber matrix affected decrease of energy loss over the mid-range strain. As a results of regression analysis, $E'\;_{max}$ correlation with ${\Delta}E'$ $(E'\;_{0.4%DSA}-E'\;_{2.0%DSA})$ showed linear relationship.

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Characteristics of Dissipation Factor in High Voltage Motor Stator Insulations (고압전동기 고정자 권선 절연재료에서 유전정접 특성)

  • Mo, Il-Soon;Kim, Hee-Dong;Lee, Young-Jun;Ju, Young-Ho
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2101-2103
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    • 1999
  • The insulation condition of stator windings was measured by dissipation factor($tan{\delta}$) test in the six high voltage motors(rated 6.6kV) which had been in service for two years. The ${\Delta}tan{\delta}$ of motor D and E was higher than that of the rest motors. The specimens were drawn out from stator windings of the high voltage motor and their were analyzed using scanning electron microscope (SEM). SEM result shows that large voids are present in the interface both turn insulation and groundwall insulation.

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Characteristics of Accelerated Aging in Generator Stator Windings (발전기 고정자 권선의 가속열화 특성)

  • Kim, Hee-Dong;Kong, Tae-Sik;Ju, Young-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.279-280
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    • 2008
  • Accelerated aging tests were conducted under laboratory conditions on two generator stator bars. Electrical stress is applied in No. 1 model stator bar. Electrical and thermal stresses are applied in No. 2 model stator bar. As aging times increased from 0 to 4780h, diagnostic tests were performed on No. 1 and No. 2 model stator bars. Diagnostic tests included AC current, dissipation factor(tan$\delta$) and partial discharge magnitude. The ${\Delta}tan{\delta}$ and $\Deta$I of No. 1 and No. 2 model stator bars increased with increased in aging time.

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A Study on electrical Characteristics of XLPE by additives (첨가제에 의한 전력 cable용 XLPE의 전기적 특성에 관한 연구)

  • 김규식;손원근;임기조;박수길
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.61-64
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    • 2000
  • Three kinds of treeing inhibitors are added to investigate the effect on electrical properties of XLPE. The treeing inhibitors are barbituric acid, 4- (4-Nitrophenylazo) resorcinol and 4-(4-Nitrophenylazo) naphthol. Added amount of each treeing inhibitors varied form 0phr to 2.0phr. In order to know the changes of electrical properties, break down strength, tan$\delta$, and $\varepsilon$$_{r}$ were measured. Experimental results showed that electrical properties of each sample was slightly changed by amount of additives.s.

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Thermal cycle test for water-cooled stator bar (수냉각 고정자 권선용 바의 열 사이클 시험)

  • Kim, Tae-Hee;Oh, Se-Wook;Lee, Jai-Kwun;Son, Sam-Yong
    • Proceedings of the KIEE Conference
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    • 2003.07c
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    • pp.1722-1725
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    • 2003
  • 절연물에 가해지는 열화 중에서 열 사이클(Thermal cycle) 열화를 모사하기 위하여, 대형 터빈 발전기 수냉각 고정자 권선용 바를 대상으로 IEEE Std 1310 규격에 따라 200 사이클의 열 사이클 열화 시험을 수행하였다. 바에 대한 절연 특성을 분석하기 위하여 시험 수행 전후의 Tan ${\delta}$ 및 Tip-up(%, ${\Delta}$ Tan ${\delta}$), 부분방전의 최대 방전량 등을 측정하였고 또한 바를 절단하여 절연물 내의 박리와 도체와 절연물 간의 분리 등을 점검하였다. 최종적으로는 절연파괴 시험을 수행하여 절연파괴 강도를 측정하였다. 시험 결과 초기 절연 특성상의 현저한 변화는 없었으며 양호한 특성을 보였다.

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Development of Vibration and Impact Noise Damping Wood-Based Composites -Synthesis of the Polymer Showing a Broad Damping Peak (진동·충격음 흡수성 목질계 복합재료의 개발 -폭 넓은 감쇠곡선을 나타내는 고분자의 합성-)

  • Lee, Hyun-Jong
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.2
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    • pp.15-22
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    • 1999
  • Polymeric meterials that are used for noise and vibration damper in wood/polymer/wood sandwich composites, must have a high loss factor(tan ${\delta}$), and at the same time the storage modulus(E) of $5{\times}10^7$ to $10^9$ dyne/$cm^2$ must withstand over a wide temperature and frequency ranges. In this study, the series of epoxy resinlpolyacrylate interpenetrating polymer networks(IPNs) were synthesized by simultaneous polymerization. Their dynamic tensile properties were measured at 110Hz using Rheovibron instrument. Composite damping factor(tan ${\delta}_c$) and dynamic bending modulus($E_c,\;E_^{\prime\prime}c$) of wood/polymer/wood sandwich composites were measured at 110Hz using a Rheovibron in bending mode of vibration. These dynamic tensile studies indicated that cured epoxy resin/polyacrylates IPNs were semicompatible in the sense that both the shifting of T($E^{\prime\prime}_{max}$) or T(tan ${\delta}_{max}$) and the broadening of glass transition temperature range were observed. Especially, the cured Epikote871/P(n-BMA) IPNs of composition 70/30 to 50/50 showed a relatively high tan a and appropriate E' value over a wide temperature range; consequently the tan a e curves of wood/IPNs/wood sandwich composites was broadened over a wide temperature range.

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Influence of Filler Composition Ratio on Properties of Both Silica and Carbon Black-Filled Styrene-Butadiene Rubber Compounds (실리카와 카본블랙으로 보강된 SBR 고무 배합물의 특성에 보강제 조성비가 미치는 영향)

  • Choi, Sung-Seen
    • Elastomers and Composites
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    • v.36 no.1
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    • pp.37-43
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    • 2001
  • Influence of the filler composition ratio on cure characteristics and bound rubber content of the compounds and on physical properties of the vulcanizates were studied using both silica and carbon black-filled styrene-butadiene rubber (SBR) compounds with the total filler content of 80.0 phr. The bound rubber content increased slightly with increase of the silica content ratio. The viscosity also increased with increasing the silica content ratio, especially increased steeply after the silica content of 60.0 phr. The cure times obtained with a rheometer, t2, t40, and t90, are increased by increasing the silica content ratio and the cure rate decreased. The delta torque increased with the increased silica content ratio. Variation or the modulus with the silica content ratio showed a decreased trend though the delta torque increased. The tan ${\delta}$ at $60^{\circ}C$ decreased with increased of the silica content ratio.

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Analysis of Insulation Characteristics of Low-Voltage Induction Motors Fed by Pulse-Controlled Inverters (인버터 구동형 저압 유동전동기의 절연특성 분석)

  • 박도영
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.195-198
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    • 2000
  • In this paper the insulation characteristics test results of 25 low-voltage induction motors($3\phi$, 5HP, 380V) are presented. Five different types of insulation techniques are applied to 25 motors. The maximum partial discharge (PD) magnitude ($\textrm{Q}_{m}$) discharge inception voltage (DIV) dissipation factor tip-up ($\Delta$tan$\delta$) and rate of change in AC current($\Delta$I) are measured by PD and AC current tests. Also the insulation breakdown tests by high voltage pulse are performed and the corresponding breakdown voltage are obtained.

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