• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
• /
• pp.24-24
• /
• 2010

In this paper, we analyzed the frequency spectrum of electromagnetic waves which is generated by series arc discharges to develop a condition monitoring technique in a closed-distribution board. We fabricated an arc generator specified in UL1699 to simulate series arc discharge. The experiment was carried out in an electromagnetic shielding room, and the measurement system consists of a Ultra Log Antenna and a EMI Test Receiver. The results showed that the frequency spectrum during series arc discharges was distributed in ranges of 30~500 [MHz], and the peak values were existed at 40 [Mhz] and 80 [MHz].

• 전기학회논문지
• /
• 제57권12호
• /
• pp.2244-2248
• /
• 2008

High intensity metal halide discharge lamp performance, specifically the generated luminous flux and light color content, depends critically on the arc tube design. Factors influencing the design and consequent lamp efficacy include : lamp size, geometry, arc tube composition, fill chemistry, electrode design and excitation modes. Shaping of Polycrystalline Alumina(PCA) can be realized by conventional ceramic processes. Several processes are applied nowadays. Well-known in the ceramic high pressure field for decades are the pressing and the extrusion method. Newly developed slurry and precious forming technologies give the one-body seamless tubes, which improve thickness uniformity and lighting performance. Now, we reported some optical properties with different arc tube structures of ceramic metal halide lamps.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
• /
• pp.1525-1526
• /
• 2006

Electrical current always travels through the minimum resistance path. In this paper, we are studied on the direction and formation of carbonized conductive path according to surface leakage between electrodes. The analysis of characteristics of the arc discharge as surface is broken down between exposed live parts. Using the HSIS(high speed imaging system, 100,000fps, redlake ltd., USA), it took photographs by arc growth mechanism occurred in on/off surge, ground fault and discharge between electrodes. Therefore, it recommended for results of technology development and application such as theoretic verification of an arc direction and economic security according to a technology about connecting arc generation in surfaces of insulators. Hereafter, it expected effects that application of energy utility technology through the arc control.

• 전기의세계
• /
• 제21권4호
• /
• pp.27-38
• /
• 1972

This paper discusses the characteristics about the ignition of D.C. main discharge is a plasma jet generator, manufactured for trial as non-transferred type, when the electrical energy appropriate to the ignition is supplied to the gap between the electrodes by using advance discharge of attenuating high frequency voltage generated by a high frequency oscillator with mercury spark gap. These characteristics are under the influences of (a) the length of mercury gap in high frequency oscillator and the quantity of hydrogen flow supplied to it, (b) the condenser capacity of the high frequency oscillator circuit, (c) the length of plasma jet torch in D.C. main discharge circuit and the quantity of argon flow supplied to it, (d) the circuit constants of D.C. main discharge circuit. The results for these characteristics, obtained by this research, are considered to be helpful to the designs for the ignition of a plasma jet as well as the welding arc stabilizer by high frequency discharge and the high frequency arc welder.

• 한국조명전기설비학회지:조명전기설비
• /
• 제10권5호
• /
• pp.66-74
• /
• 1996

본 연구는 자계내에서 직류 차단설비의 아크소호 현상을 규명하기 위하여 침대 평판 전극에 부극성 직류 고전압 인가시 아크전압 및 전류 그리고 이들 파형특성을 자계세기의 변화에 따라 연구 검토하였다. 본 연구에서 얻은 중요한 결론은 다음과 같다. 자계가 인가되지 않았을 때는 아크동특성이 나타나지 않고 아크전압의 감소와 아트전류의 증가가 순간적으로 이루어진 후, 일정하게 유지되었을 뿐만아니라 전류 파형으로부터 아크방전이 연속적으로 발생됨을 알수 있었다. 자계가 인가되면 아크동특성이 나타난후, 서서히 아크전압이 감소되고 증가되고 아크전류는 감소되었다. 그리고 전류파형으로부터 아크방전은 단속적으로 됨에 따라 전류영점이 나타남을 알 수 있었고, 전류영점이 나타나는 주기와 아크방전의 단속 주기가 일치하였으며 자계가 증가될수록 주기도 증가되었다.

• 한국분말재료학회지
• /
• 제11권6호
• /
• pp.510-514
• /
• 2004

Iron-carbon nanocapsules were synthesized by plasma arc discharge (PAD) process under various atmosphere of methane, argon and hydrogen gas. Characterization and surface properties were investigated by means of HRTEM, XRD, XPS and Mossbauer spectroscopy. Fe nanocapsules synthesized were composed of three phases $({\alpha}-Fe,\;Y-Fe\;and\;Fe_{3}C)$ with core/shell structures. The surface of nanocapsules was covered by the shell of graphite phase in the thickness of $4{\~}5$nm.

• 한국분말재료학회지
• /
• 제11권6호
• /
• pp.522-527
• /
• 2004

Nano sized FeAl intermetallic particles were successfully synthesized by plasma arc discharge pro-cess. The synthesized powders shouted core-shell structures with the particle size of 10-20 nm. The core was metallic FeAl and shell was composed of amorphous $AI_{2}O_{3}\;and\;a\;little\;amount\;of\;metallic\;Fe_{3}O_{4}.$ Because of the difference of Fe and Al vapor pressure during synthesis, the Al contents in the nanoparticles depended on the Al contents of master alloy.

• 한국분말재료학회지
• /
• 제10권1호
• /
• pp.51-56
• /
• 2003

To investigate the effect of the parameters of the plasma arc discharge process on the particle formation and particle characteristics of the iron nano powder, the chamber pressure, input current and the hydrogen volume fraction in the powder synthesis atmosphere were changed. The particle size and phase structure of the synthesized iron powder were studied using the FE-SEM, FE-TEM and XRD. The synthesized iron powder particle had a core-shell structure composed of the crystalline $\alpha$-Fe in the core and the crystalline $Fe_3O_4$ in the shell. The powder generation rate and particle size mainly depended on the hydrogen volume fraction in the powder synthesis atmosphere. The particle size increased simultaneously with increasing the hydrogen volume fraction from 10% to 50%, and it ranged from about 45nm to 130 nm.

• 한국분말재료학회지
• /
• 제11권4호
• /
• pp.328-332
• /
• 2004

Fe nanopowders were successfully synthesized by plasma arc discharge (PAD) process using Fe rod. The influence of chamber pressure on the microstructure was investigated by means of X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The prepared particles had nearly spherical shapes and consisted of metallic cores (a-Fe) and oxide shells (Fe$_{3}$O$_{4}$), The powder size increased with increasing chamber pressure due to the higher dissolution and ejection rate of H$_2$ and gas density in the molten metal.

• 한국진공학회지
• /
• 제12권S1호
• /
• pp.21-27
• /
• 2003

Micro-arc discharge oxidation (MDO) is a cost-effective plasma electrolytic process which can be used to improve the wear and corrosion resistance of Al-alloy parts by forming a alumina coating on the component surface. However, the MDO coated Al-alloy components often exhibit relatively high friction coefficients and low wear resistance fitted with many counterface materials, additionally, the pitting corrosion for the MDO coated AI-alloy components, especially for a thinner alumina coating, often occurs in atmosphere circumstance due to the porous alumina coats. Therefore, a duplex treatment, combining a MDO coated ahumina thin layer with a TiN coating, prepared by magnetron sputtering (MS), has been investigated. The Vicker's microhardness, pin-on-disc, electrochemical measurement, salt spray, XRD and SEM tests were used to characterize and analyze the treated samples. The work demonstrates that the MDO/MS coated samples have a combination of a very low friction coefficient and good wear resistance as well as corrosion since the micro-holes on alumina coating are partly or fully covered by TiN material.