• Title/Summary/Keyword: Electric characteristic

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A Characteristic of Tracking Progress Happened at the End of the VCTFK (VCTFK 끝단에서 발생되는 트래킹의 진전특성)

  • Jee, Seung-Wook;Kim, Shi-Kuk;Ok, Kyung-Gea;Lee, Chun-Ha;Lee, Kwang-Sik
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.8
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    • pp.78-83
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    • 2010
  • This paper describes the characteristic of tracking progress happened at the end of the polyvinyl chloride insulated cabtyre oval cord(VCTFK) that is widely used for distribution cord. Tracking is occurred owing to the drop of electrolyte at the end of the VCTFK. The tracking progress and its characteristic happened at the end of the VCTFK are as follow; Carbonization and electrical erosion are happened at the end of the VCTFK. Electrical erosion is begun at the insulation layer near conductors. After that, it is also happened at the sheath layer. Accumulation of carbonized insulation and sheath materials at the end of the VCTFK is begun after progress of electrical erosion. When the accumulation is progressed arc discharge is appeared and finally it goes to tracking breakdown.

Semiconductor Engineering (산화물반도체 트랜지스터의 전기적인 특성)

  • Oh, Teresa
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.10a
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    • pp.390-392
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    • 2013
  • The research was observed the characteristic of ZnO based oxide semiconductors for the transparent conducting display. The optical-physical properties of ZnO based oxide semiconductors) grown on p-Si wafer were presented. ZnO based oxide semiconductors was prepared by the RF magnetron sputtering system. The characteristic of ZnO based oxide semiconductorswas strongly influenced by the amount of localized electron state by the defects. The PL spectra moved to long wave number with increasing the defects in the film. The mobility of a-IGZO film was increased with increasing the oxygen gas flow rate. The resistivity of ZnO based oxide semiconductors was also related to the mobility of ZnO based oxide semiconductors, and the mobility increased at the sample with low resistivity. The electric characteristic of a-IGZO TFTs showed that it is an n-type semiconductor.

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Dynamic Characteristic Analysis of Linear DC Motor by 3D EMCN Considering Input Voltage (구동 전압을 고려한 3차원 등가자기회로방법에 의한 선형 직류전동기의 동특성 해석)

  • Ha, Kyung-Ho;Yeom, Sang-Bu;Hong, Jung-Pyo;Hur, Jin;Kang, Do-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.2
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    • pp.61-68
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    • 2002
  • In order to design the Linear DC Motor (LDM) with improved characteristics, transient and steady state analysis are required. furthermore, 3D analysis is also needed to analyze the precise characteristics like thrust, time harmonics. This paper deals with the transient and dynamic characteristic analysis of LDM by coupling of external circuit and motion equation using 3D Equivalent Magnetic Circuit Network Method (EMCN). For the three dimensional analysis of electric machine, EMCN is very effective method that ensures high accuracy similar to FEM and short computation time. Also, The modeling by EMCN easily allows the mover to move with respect to the stater at each time step, and the spatial moving step is determined by the solution of the mechanical motion equation and the computed electromagnetic thrust The results are compared with experimental ones to clarify the usefulness and verify the accuracy of the Proposed method.

An Analysis of the I-t Characteristic of Low Voltage Distribution Line Fuse Using the FEM (유한 요소법을 이용한 저압 배전용 전선퓨즈의 I-t 특성 해석)

  • 황명환;박두기;이세현;한상옥
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.11 no.6
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    • pp.74-80
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    • 1997
  • In this paper, we deal with the I -t characteristic of low voltage distribution fuse (line fuse). That fuse element has two parts;One is low temperature melting element(LTME) to put up with over current and the other is high temperature melting element (HTME) which put up with large current. Melting charateristic of fuse is determined by L TME and HTME. So we verified their properties of fuse design, mathematically, by simulating the thermal and electric characteristics of each other. We simulated the I-t characteristic of line fuse by using the numerical method;Finite Element Method(FEM). Then, we could acquire very similar result at the HTME and L TME area when compared the simlation result with experimental one.

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A Study on Improvement of Cooling Performance through Vent Structure Optimization of Carbon Ceramic Composite Disc (카본 세라믹 복합재 디스크의 벤트 구조 최적화를 통한 냉각성능 향상에 관한 연구)

  • Shim, J.H.;Shin, U.H.;Lee, J.H.;Jeon, G.B.;Kim, B.C.;Kwack, J.H.;Lim, D.W.;Hyun, E.J.;Jeon, T.H.;Lee, J.M.
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.1
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    • pp.23-29
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    • 2019
  • Recently, use of composite materials has been increasing for body structures and chassis parts in the car industry because of weight reduction effect and excellent mechanical thermal characteristics. However, application of composite materials in brake system is very difficult because it is hard to obtain enough brake performance due to low heat storage capacity of the composite materials. In this paper, we will present new carbon ceramic composite disc with high flow characteristic. To obtain this characteristic, new vent structures were designed by using ARIZ method and substance-field model analysis. The flow effect of these vent structures on the brake performance was verified by pugh matrix and cooling test. The test results show improvement of cooling performance up to $30^{\circ}C$. Finally, These results will improve brake the reliability of the brake performance for the high performance vehicles and electric vehicles.

Characteristics of a 190 kVA Superconducting Fault current Limiting Element (190 kVA급 초전도한류소자의 특성)

  • Ma, Y.H.;Li, Z.Y.;Park, K.B.;Oh, I.S.;Ryu, K.Y.
    • Progress in Superconductivity and Cryogenics
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    • v.9 no.1
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    • pp.37-42
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    • 2007
  • We are developing a 22.9 kV/25 MVA superconducting fault current limiting(SFCL) system for a power distribution network. A Bi-2212 bulk SFCL element, which has the merits of large current capacity and high allowable electric field during fault of the power network, was selected as a candidate for our SFCL system. In this work, we experimentally investigated important characteristics of the 190 kVA Bi-2212 SFCL element in its application to the power grid e.g. DC voltage-current characteristic, AC loss, current limiting characteristic during fault, and so on. Some experimental data related to thermal and electromagnetic behaviors were also compared with the calculated ones based on numerical method. The results show that the total AC loss at rated current of the 22.9 kV/25 MVA SFCL system, consisting of one hundred thirty five 190 kVA SFCL elements, becomes likely 763 W, which is excessively large for commercialization. Numerically calculated temperature of the SFCL element in some sections is in good agreement with the measured one during fault. Local temperature distribution in the190 kVA SFCL element is greatly influenced by non-uniform critical current along the Bi-2212 bulk SFCL element, even if its non-uniformity becomes a few percentages.

Residence Time Distribution in the Chromatographic Column: Applications in the Separation Engineering of DNA

  • Park, Young G.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.8 no.2
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    • pp.117-125
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    • 2003
  • Experimental and theoretical works were performed for the separation of large polyelectrolyte, such as DNA, in a column packed with gel particles under the influence of an electric field. Since DNA quickly orient in the field direction through the pores, this paper presents how intraparticle convection affects the residence time distribution of DNAs in the column. The concept is further illustrated with examples from solid -liquid systems, for example, from chromatography Showing how the column efficiency is improved by the use of a n electric field. Dimensionless transient mass balance equations were derived, taking into consideration both diffusion and electrophoretic convection. The separation criteria are theoretically studied using two different Peclet numbers in the fluid and solid phases. These criteria were experimentally verified using two different DNAs via electrophoretic mobility measurements. which showed how the separation position of the DNAs varies in the column in relation to the Peg/Pef values of an individual DNA. The residence time distribution was solved by an operator theory and the characteristic method to yield the column response.

Functionalization of Wool Fiber Using Water-Soluble C-60 (수용성 C-60을 이용한 양모섬유의 기능화)

  • Jeon, Yeong-Sil;Gwon, Hyeok-Seong;Nam, Seong-U;Kim, In-Hoe
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 2008.04a
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    • pp.77-79
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    • 2008
  • Polynitro fullerenes were synthesized by reaction C-60 in benzen solution with a mixture of NaNO$_2$ and HNO$_3$. Hydrolysis of polynitro fullerenes in aqueous NaOH gave the corresponding polyhydroxylated fullerenes. Sulfonation reaction was carried out in pyridine solution of ClSO$_3$H. Infrared spectra of the resultant fullerene derivatives showed the characteristic IR bands, corresponding to absorptions of O-H, N-O, and SO$_3$Na functions. Electric resistivity and thermal transmittance of wool fiber absorbed with the water-soluble C-60 were investigated. Thermal transmittances of wool fiber were increased with increasing water-soluble C-60 concentrations, but electric conductivity were decreased with raising water-soluble C-60 uptake values.

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Scott Transformer Modeling using Simulink on the AC Substation (Simulink를 이용한 교류 급전변전소의 스코트변압기 모델링)

  • Kim, Tae-Geun;Park, Young;Lee, Jong-Woo
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2317-2322
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    • 2011
  • In three-phase power, when the power is supplied to the single phase load, there is the unbalance of load in the three-phase power. So the scott transformer is used in the power system to supply a single phase load in three-phase power without the unbalance of loads. Especially, the scott transformer is used in the AC substation of electric railroad. Two single phase transformers are combined by T-wiring in the scott transformer. So, two single phase voltage is provided by differing $90^{\circ}$ phase in three-phase power. The selection of related equipment and correction of protective relay are not easy from characteristic of the scott transformer when shunt and ground faults occur. In this paper, electric model of the scott transformer is suggested and the current of the scott transformer in shunt and ground faults is analyzed. Also, the scott transformer model is demonstrated by using Sinulink.

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Analysis on Wearing Characteristics of Main Wearing Slider for Pantograph According to Precipitation (강수의 영향에 따른 Pantograph 주습판의 마모특성 분석)

  • Kim, Kyung-Seob;Kim, Kwan-Soo;Cho, Kwan-Hyun
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.994-999
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    • 2011
  • The main wearing slider of pantograph is a difference which is considerable to wear phenomenon according to material properties. Especially, Cu-type wearing slider suddenly occurs the abnormal wear by precipitation, this threatens the travelling safety of the train. The abnormal wear by precipitation and arc influences are main factor decided to life time of Cu-type wearing slider and contact wire. Consequently, the application of the main wearing slider with wear resisting capacity, electrical conductivity, resistance arc and lubrication is demanded. In this paper through tribologic approach, overcame abnormal phenomenon of the Cu-type wearing slider by the precipitation and for the economic efficient augmentation by durability improvement and the travelling safety were accomplished. The Cu-type wearing slider which has excellent electric conductivity and arc characteristic but it occurs the normal and abnormal wear phenomenon according the precipitation which changes, respectively. Consequently, this phenomenon grasps fixed quantity according to precipitation, a mileage and wear volume then Fe-type wearing slider compared and analyzed.

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