• Title/Summary/Keyword: arc-discharge

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ARC Discharge Sound Source in Underwater (수중 아-크 방전음원에 관한 연구)

  • Chang, Jea-Hwan;Chang, Jee-Won
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.21 no.1
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    • pp.12-18
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    • 1985
  • In general the impulse sound sources of underwater generated by electric arc discharge had used static energy of the charged capacitors. The author proposed an underwater arc discharge sound source using secondary voltage of high voltage transformer without capacitors. The arc discharge device was composed of a high voltage transformer and a switching system. The impulse current in the primary turn of the high voltage transformer is controlled by the switching system and inductive current of the secondary turn in the high voltage transformer is used in making impulsive arc discharge. A series of experiment have been carried out to observe the acoustic characteristics of the impulse sound source generated by the arc discharge. The results obtained were as follows: 1. Secondary current at the time of arc discharge keeps after ohm's law in the beginning and the maximum current flows out as soon as arc discharge breaks out. 2. A time difference between a start of applied current and a generation of arc discharge sound is the 3msec and it is generated arc sound when breaking down electric insulation at maximum voltage. 3. The sharper the end of electrodes and the higher the secondary voltage, the higher the sound pressure level. 4. Arc discharge sound was generated even at the distance of 100cm between electrodes and was stably reproductive at the gap of 1cm to 100cm. 5. Electric arc discharge sound wave is a shock wave of pulse-width of 0.15msec and spectral distribution of it is plenty of low frequency components less than 10 KHz.

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A Study on Energy Recovery Circuit in Sputtering Plasma Power supply for arc Discharge Prevention (스퍼터용 플라즈마 전원장치의 아크방지를 위한 에너지 회생회로에 대한 연구)

  • Ban, Jung-Hyun;Han, Hee-Min;Kim, Joohn-Sheok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.61 no.3
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    • pp.116-121
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    • 2012
  • Recently, in the field of renewable energy such as solar cells including the semiconductor and display industries, thin film deposition process is being diversified. Furthermore, to deal with trend of making high-quality and fast, the high-capacity and output plasma power supply which can control high density plasma is required. The biggest problem is arc discharge caused by using high voltage power supply. Thus, the key function of plasma power supply is to prevent arc discharge and there is a need to maintain the possible minimum arc energy. In DC sputtering power supply, on a periodic basis (-)voltage powering up is able to significantly reduce arcing, as well as arc discharge prevention, and maintaining uniform charge density. This conventional method for powering up (-)voltage requires heavy mutual inductance of the transformer to avoid distortion problem of the output voltage. This study is about energy recovery circuit for arc discharge prevention in sputtering plasma power supply. By using energy recovery circuit, it is possible to reduce the mutual inductance and size of the transformer dramatically, prevent distortion of the output voltage and has a stable output waveform. This work was proved through simulation and experimental study.

Analysis of Contact Loss Arc Spectrum between Contact Wire and Pantograph Material using a Spectrometer (광계측기를 이용한 전차선-팬터그래프 재질별 이선아크 스펙트럼 분석)

  • Chang, Chin-Young;Jung, No-Geon;Park, Jong-Gook;Koo, Kyung-Wan;Kim, Jae-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1803-1808
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    • 2013
  • To maintain contact between catenary and pantograph copper is important in order to transmit power smoothly on Current collection system. But, Arc discharge with strong light is generated because of contact loss. Therefore, Arc discharge detection is important measurement factor judging performance of current collection system. In this paper, It is described to results of arc discharge applying UV detection technology using arc generator. And Arc discharge was detected using the most commonly used processing catenary and rigid catenary and pantograph copper of electric rolling stock for securing arc detection instrument reliability. Results of contact loss detection instrument in this paper will be used for maintenance of current collection quality and system.

Characteristics of RC Circuit with Transistors in Micro-EDM (트랜지스터 부착 RC 방전회로의 마이크로 방전가공 특성)

  • Cho Pil Joo;Yi Sang Min;Choi Deok Ki;Chu Chong Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.12
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    • pp.44-51
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    • 2004
  • In a micro-EDM, it is well known that an RC circuit is suitable as a discharge circuit because of its low pulse width and relatively high peak current. To increase machining speed without changing unit discharge energy, charge resistance should be decreased. But, when the resistance is very low, continuous (or normal) arc discharge occurs, electrode wear increases and machining speed is reduced remarkably. In this paper, an RC circuit with transistors is used in a micro-EDM. Experimental results show that the RC circuit with transistors can cut off a continuous (o. normal) arc discharge effectively if the duty factor and switching period of the transistor are set up optimally. Through experiments with varying charge resistances, it is shown that the RC circuit with transistors has about two times faster machining speed than that of an RC circuit.

Characteristics of RC circuit with Transistor in Micro-EDM (트랜지스터 부착 RC 방전회로의 마이크로 방전가공 특성)

  • 조필주;이상민;최덕기;주종남
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.235-240
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    • 2002
  • In micro-EBM, it is well blown that RC circuit is suitable for discharge circuit because of its low pulse width and relatively high peak current. To increase machining speed without changing unit discharge energy, charge resistance should be decreased. But, if very low, continuous (or normal) arc discharge occurs, then increases electrode wear and reduces machining speed remarkably. In this paper, RC circuit with transistor is used to micro-EDM. Experimental results show that RC circuit with transistor can cut off continuous (or normal) arc discharge effectively if duty factor and switching period of transistor are set up optimally. Through experiments with varying charge resistance, it can be known that RC circuit with transistor has about two times faster machining speed than that of RC circuit. Especially, it has prominent rise-effect of machining speed in low unit discharge energy, so that a high-quality and high-speed micro-EDM can be realized through RC circuit with transistor.

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Hydration Properties of Cement Matrix using Surface Treatment Blast Furnace Slag by Arc Discharge (아크방전에 의해 표면개질 된 고로슬래그를 사용한 시멘트 경화체의 수화 특성)

  • Kim, Sun-A;Kim, Hyeon-Sung;Park, Sun-Gyu
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.91-92
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    • 2018
  • A glassy thin film was formed on the surface of the blast furnace slag. When blast furnace slag is used as an admixture of concrete, addition of alkali activators were required. However, alkali activators are not only dangerous as chemical products, but they are also difficult to use as expensive materials. Therefore, it is necessary to study the way of removal of the glassy thin film of blast furnace slag without the risk and cost increase. In this study, to solve this problem, experiment was carried out to improve the hydration reactivity by treatment the surface of blast furnace slag using arc discharge. Experimental results show that when the surface of the blast furnace slag was tratmented by arc discharge, the glassy thin film was destroyed. And the hydration reactivity was improved, the compressive strength was increased.

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Arc Discharge Sensor having Noise Immunity to Ambient Light (주변광 영향을 받지 않는 아크방전 감지 센서)

  • Roh, Hee Hyuk;Seo, Yong Ma;Khishigsuren, J.;Choi, Kyoo Nam
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.726-728
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    • 2013
  • Optoelectronic arc discharge sensor was used to detect arc discharge inside power distribution panel. Arc discharge is fatal to power system once it begins, thus preventive detection is necessary before power failure occurs. Optoelectronic detection method was used to avoid direct electrical contact to power apparatus inside power distribution panel. 180 degree detection angle and detection range far exceeding 6m, which was sufficient for monitoring purpose, was achieved using the photodiode having $7.5mm^2$ of active surface area and flash source with $0.4cal/cm^2$ energy density, which is equivalent to 1.9J with $2.16cm^2$ emitting area. The response speed of arc discharge sensor was measured to be below 1 msec. The above optoelectronic arc discharge sensor was measured to be sensitive enough to detect 0.94 pC charge.

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Single Wall Carbon Nanotube Films Produced by Arc Discharge (아크 방전법으로 성장된 대면적 단일벽 탄소나노튜브 필름)

  • Kang, Young-Jin;Oh, Dong-Hoon;Song, Hye-Jin;Jung, Jin-Yeun;Jung, Hyuk;Cho, You-Suk;Kim, Do-Jin
    • Korean Journal of Materials Research
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    • v.18 no.5
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    • pp.253-258
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    • 2008
  • A simple method to deposit carbon nanotube films uniformly on large area substrates using an arc discharge method is reported in this paper. The arc discharge method was modified to deposit carbon nanotube films in situ on the substrates. The substrates were scanned several times over the arcing point for a uniform film thickness. Deposition was carried out under variable dc bias conditions at 600 torr of $H_2$ gas. The thickness uniformity of the single-wall carbon nanotube films as characterized by a four-point probe was within 30% deviation. The morphology and crystal quality of the single-wall carbon nanotube film were also characterized by field emission scanning electron microscopy and Raman spectroscopy.

Field emission properties of SWNTs (single-walled nanotubes) synthesized by arc-discharge method (Arc-Discharge로 합성한 SWNT의 전계방출 특성)

  • Lee, Hyeon-Jae;Lee, Yang-Doo;Moon, Seung-Il;Hwang, Ho-Soo;Han, Jong-Hoon;Yoo, Jae-Eun;Nahm, Sahn;Ju, Byeong-Kwon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.185-188
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    • 2004
  • A diode structure of field emission lamps based upon carbon-nanotube is studied. The single-walled carbon nanotubes(SWNTs) were produced by arc discharge method. We made the 1-inch diode type flat lamp using CNTs. We applied anode voltage gradually to refine the field emission behavior of emitter in dynamic vacuum system to study the emission current. the brightness and efficiency, etc. The field emission properties was estimated by varying gaps between the cathode and anode, contents of the glass frit. The good luminous efficiency is showed in the gap $900{\mu}m$, $1200{\mu}m$ and contents of the proper glass frit. For the upper conditions, the luminous efficiencies were respectively 23.30, 11.12 1m/W.

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