• 전기학회논문지P
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• 제61권3호
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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.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권3호
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• pp.130-136
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• 2003

Crowbar system Vacuum switches, widely used In a pulsed power system, could use the magnetic force to prevent the electrode damage. Vacuum switches using the magnetic forces are classified roughly into RMF(Radial Magnetic Field) and AMF(Axial Magnetic Field) type. The RMF type switches restrain a main electrode from aging due to high temperature and high density arc by rotating the arc which is driven by the Lorenz force. The AMF type switches generate axial magnetic field which decreases the electrode damage by diffusing arc. In this paper, we present the energy loss characteristics of both RMF and AMF type switches which are made of CuCr(75:25 wt%) electrodes. The time-dependent dynamic arc resistance of high-current pulsed discharge in a high vacuum chamber(~10$^{-6}$ Torr). which occurs in RMF and AMF type switches, was obtained by solving the circuit equation using the measured values of the arc voltage and current. In addition, we compared energy loss characteristics of both switches. Based on our results, it was found that the arc voltage and the energy loss of an AMF type switch are lower than a RMF type switch.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 추계학술대회 논문집
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• pp.30-33
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• 2004

In order to analyze the heat transfer phenomena in the plasma flames, a mathematical model describing heat and fluid How in an electric arc has been developed and used to predict heat transfer from the arc to the steel bath in a DC Electric Arc Furnace. The arc model takes the separate contributions to the heat transfer from each involved mechanism into account, i.e. radiation, convection and energy transported by electrons. The finite volume method and a SIMPLE algorithm are used for solving the governing MHD equations, i.e., conservation equations of mass, momentum, and energy together with the equations describing a standard $k-\varepsilon$ model for turbulence. The model predicts heat transfer for different currents and arc lengths. Finally these calculation results can be used as a useful insight into plasma phenomena of the industrial-scale electric arc furnace. from these results, it can be concluded that higher arc current and longer arc length give high heat transfer.

• 전기학회논문지P
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• 제66권4호
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• pp.200-205
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• 2017

In this paper, we propose a technique to determine the normal and arc of an alternating current using a mixed filter composed of an average filter and a band-pass filter and a frequency analysis. The proposed method uses the moving average filter of the FIR filter structure for noise removal and the band-pass filter of the IIR filter structure for detecting only specific frequency components after normalizing the measured current signal based on the maximum value. After performing Fast Fourier Transform (FFT) using the band-pass filtered signal, the total energy is calculated using the magnitude component of the frequency, and the arc is detected using the magnitude of the calculated energy. In order to show the validity of the proposed method, we experimented with various data and found that arc and steady state can be easily discriminated by calculating spectral energy. Therefore, it is considered that the proposed method can be applied to arc diagnosis of low voltage electric wire.

• Radiation Oncology Journal
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• 제1권1호
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• pp.29-36
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• 1983

The treatment of tumors along curved surfaces with stationary electron beams using cone collimation may lead to non-uniform dose distributions due to a varying air gap between the cone surface and patient. For large tumors, more than one port may have to be used in irradiation of the chest wall, often leading to regions of high or low dose at the junction of the adjacent ports. Electron-beam arc therapy may elimination many of these fixed port problems. When treating breast tumors with electrons, the energy of the internal mammary port is usually higher than that of the chest wall port. Bolus is used to increase the skin dose or limit the range of the electrons. We invertiaged the effect of various arc beam parameters in the isodose distributions, and combined into a single arc port for adjacent fixed ports of different electron beam eneries. The higher fixed port energy would be used as the arc beam energy while the beam penetration in the lower energy region would be controlled by a proper thickness of bolus. We obtained the results of following: 1. It is more uniform dose distribution of electron to use rotation than stationary irradiation. 2. Increasing isocenter depth on arc irradiation, increased depth of maximum dose, reduction in surface dose and an increasing penetration of the linear portion of the curve. 3. The deeper penetration of the depth dose curve and higher X-ray background for the smaller field sized. 4. If the isocenter depth increase, the field effect is small. 5. The decreasing arc beam penetration with decreasing isocenter depth and the isocenter depth effect appears at a greater depth as the energy increases. 6. The addition of bolus produces a shift in the penetration that is the same for all depths leaving the shape of the curves unchanged. 7. Lead strips 5 mm thick were placed at both ends of the arc to produce a rapid dose drop-off.

• Journal of Advanced Marine Engineering and Technology
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• 제28권8호
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• pp.1251-1257
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• 2004

In order to analyze the heat transfer phenomena in the plasma flames, a mathematical model describing heat and fluid flow in an electric arc has been developed and used to predict heat transfer from the arc to the steel bath in a DC Electric Arc Furnace. The arc model takes the separate contributions to the heat transfer from each involved mechanism onto account, that is radiation, convection and energy transported by electrons. The finite volume method and a SIMPLE algorithm are used for solving the governing MHD equations, that are conservation equations of mass, momentum and energy together with the equations describing a standard k-${\varepsilon}$ model for turbulence. The model predicts heat transfer for different currents and arc lengths. Finally these calculation results can be used as a useful insight into plasma phenomena of the industrial-scale electric arc furnace. From these results, it can be concluded that higher arc current and longer arc length give high heat transfer

• Journal of Advanced Marine Engineering and Technology
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• 제11권4호
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• pp.33-40
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• 1987

Arc power is consumed energy per unit time between welding electrodes. The relations between consumed energy and electrode distance, current, voltage are nonlinear characteristics. Therefore commercial A.C. wattmeter cannot be used for measurement of the arc power. Most of arc energy measuring systems are developed for relay contact arc measurement. Relaly arc requires integrated instantaneous power because relay arc finishes in a short instant. But most of welding powers are continually consumed powers, therefore instantaneous power must be continually indicated in the form of averagy value. The author propose a new measurement method of power in which the current and voltage of welding electrode is multiplied and the resultant signal is passed to low pass filter in order to remove higher order frequency components. After integrating, the signal is devided by the integral interval and the results are stored in a computer memory.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1996년도 제10회 학술발표회 논문개요집
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• pp.164-164
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• 1996

• 전기학회논문지P
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• 제66권3호
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• pp.144-149
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• 2017

There is a little research on DC arc detection when compared to a large number of literature and patents on AC arc detection. However, as DC energy sources such as photovoltaic power generation facilities and fuel cells are introduced, research on DC arc has become as important as AC arc detection in terms of circuit protection and system reliability enhancement. In this paper, we have developed an arc detection method for photovoltaic system using frequency analysis. Through various experiments, it was confirmed that the proposed method effectively detects the arc.

• 전기학회논문지P
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• 제58권3호
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• pp.362-368
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• 2009

Electrical fires have been occurred continuously in spite of installing ELB. Therefore the concern with the electrical arc-fault that cause the fire has growing. This paper measured series arc fault currents by the method of arc generator test in UL standard 1699. The used analysis methods in this paper are three different ways using DWT(discrete wavelet transform) those are frequently used for the arc fault current signal analysis. The arc fault detection probability is 100 % by method using noise-energy/shoulder-duration ratio of approximation coefficient. As these results, the variation of noise-energy and shoulder-duration ratio of approximation coefficient are founded important factors for the analysis of arc fault.