• Title, Summary, Keyword: arc

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Thyristor Rectifier for DC Arc Furnace with Enhanced Arc Stability

  • Jung, Kyungsub;Suh, Yongsug;Kim, Taewon;Park, Taejun
    • Proceedings of the KIPE Conference
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    • pp.498-499
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    • 2011
  • In this paper, the fundamental features of the arc stability DC arc furnace have been investigated, from the converter point of view. To compare of measurement arc data from DC arc furnace and the advanced arc simulations of magneto-hydrodynamics (MHD) and the well known Cassie-Mayr arc model have been extensively used. The MHD based arc simulation has been validated in the subcomponent level, for the free burning arc set up in the laboratory. The arc simulation predicted the arc voltage for different currents with the accuracy which satisfies engineering requirements. It has been shown that the arc current steepness at current zero determines the arc stability, and the associated peak arc resistance can be used as its quantitative measure. Based on the presented insight into the DC arc stability, a converter topology solution which realizes an optimal arc stability has been proposed. The main results presented in this paper provide a design guideline for the future DC arc furnace converter topology developments.

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A Study of DC Arc Detection Device (DC Arc 검출장치에 대한 연구)

  • Ban, Gi-Jong;Kim, Lark-Kyo;Nam, Moon-Hyun
    • Proceedings of the KIEE Conference
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    • pp.98-100
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    • 2007
  • DC Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, DC arc detection device is designed for the display of DC arc fault current which is occurred in the local electric network with DC Power. This DC arc is one of the main causes of electric fire. Arc fault in electrical network has the characteristics of low current, high impedance and low frequency. DC Arc current detection device is designed for the display of arc fault current which has the modified arc characteristics.

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Control Strategy of Smoothing Arc for DC Arc Furnace

  • Jung, Kyungsub;Suh, Yongsug;Lee, Yongjoong;Kim, Taewon;Park, Taejun
    • Proceedings of the KIPE Conference
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    • pp.354-355
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    • 2013
  • Fundamental features of the arc stability in DC arc furnace of 720V/100kA/72MW have been investigated. Cassie-Mayr arc model has been employed and applied for the target dc arc furnace. In order to characterize the parameters of Cassie-Mayr arc model and the behavior of unstable arc dynamics, the advanced arc simulations of magneto-hydrodynamics (MHD) has been performed. The MHD based arc simulation has been validated in the subcomponent level, for the free burning arc set up in the laboratory. From the results of MHD simulation, dc arc dynamic resistance is proposed to be an effective arc stability function reflecting the instability of dynamic arc behavior. The experimental result confirms the usefulness of proposed dynamic arc resistance as arc stability function. The proposed arc stability function can be regarded as an effective criterion for the overall power conversion system to maintain highly stable arcing operation leading to better productivity and reliability.

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Development of Fuzzy Controller for Stabilizing the Arc State in Gas Metal Arc Welding (GMA 용접에 있어서 아크 안정화를 위한 퍼지제어기 개발에 관한 연구)

  • Kang, Moon-Jin;Lee, Se-Hun
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.12
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    • pp.152-160
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    • 1999
  • The weld quality of $CO_2$ arc welding is closely related to the arc stability. As the characteristics of the arc are excessively complex and nonlinear, it is not easy to make the arc model as mathematical form and to control the arc state to be stabilized. This paper was aimed to estimate the arc stability and to control for stabilizing the arc state in short circuit metal transfer mode of $CO_2$ arc welding. For these purposes, the behaviors of arc stability was investigated at different welding conditions using Mita's arc stability index, and the fuzzy control algorithm which uses the arc stability index as control imput and the arc voltage as control output was developed. In the control of the arc stability, the experiments of two cases were performed; the case of setting an initial welding voltage arbitrarily, the case of the step change in workpiece shape. Obtained results were as follows; Mita's arc stability index was able to be estimated qualitatively in the case of using the inverter type welding power source and the control performance for stabilizing the arc status was excellent in the case of existing step change disturbance.

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Control Algorithm of Thyristor Rectifier to Improve Arc Stability in DC Arc Furnace

  • Jung, Kyungsub;Suh, Yongsug;Kim, Taewon;Park, Taejun
    • Proceedings of the KIPE Conference
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    • pp.371-372
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    • 2012
  • In this paper fundamental features of the arc stability in DC arc furnace of 720V/100kA/72MW have been investigated. Cassie-Mayr arc model has been employed for the target dc arc furnace. In order to characterize the parameters of Cassie-Mayr arc model and the behavior of unstable arc dynamics, the advanced arc simulations of magneto-hydrodynamics (MHD) has been performed. Based on the results of MHD simulation, dc arc dynamic resistance is proposed to be an effective arc stability function reflecting the instability of dynamic arc behavior. The experimental result confirms the usefulness of proposed dynamic arc resistance as arc stability function. The proposed arc stability function can be regarded as an effective criterion for the overall power conversion system to maintain highly stable arcing operation leading to better productivity and reliability.

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A Study on the Development of Arc Length Estimation Method in FCAW (FCAW에서의 아크 길이 추정 방법 개발에 관한 연구)

  • Bae, Kwang-Moo;Cho, Sang-Myung
    • Journal of Welding and Joining
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    • v.27 no.3
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    • pp.67-72
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    • 2009
  • The flux cored arc welding (FCAW) process is one of the most frequently employed and important welding process due to high productivity and excellent workability. The process is performed either as an automated process or as a semi-automatic process. In FCAW process, welding voltage has been considered as a qualitative indication of arc length. But it is necessary to let welding operators know, maintain and manage the arc length directly by estimating and displaying it. In this study, to develop arc length estimation technique, we measured a welding circuit resistance($R_sc$) and then we calculated welding circuit voltage drop($V_sc$). Also, we measured arc peak voltage($V_ap$). By subtracting $V_sc$ from $V_arc$, we can easily calculate net arc voltage drop($V_arc$). Consequently, we suggested arc length estimating equation and basic algorithm by regressive analyzing the relationship between net arc voltage drop($V_arc$) and real arc length(Larc) measured by high speed camera. Therefore, arc length can be predicted by just monitoring welding current and voltage.

Study on Corrosion Resistance Performance of Zn Coating Applied by Arc Thermal and Plasma Arc Spray Process in Artificial Ocean Water (인공해양환경에서 Arc Thermal and Plasma Arc Spray 공법이 적용된 Zn 코팅 강재의 내식성능 평가에 관한 연구)

  • Jannat, Adnin Raihana;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.83-84
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    • 2020
  • In present study, we have deposited the Zinc coating using arc thermal spray and plasma arc spray processes onto the steel substrate and durability of the deposited coating was evaluated. The bond adhesion result shows that plasma arc sprayed Zn coating exhibited higher in its value compared to arc thermal spray. SEM shows that Zn coating deposited by plasma arc process is more compact, less porous and adherent compare to arc spray process. The corrosion resistance properties are evaluated in artificial ocean water solution with exposure periods. EIS results show that total impedance at 0.01 Hz of plasma arc sprayed coating is higher than arc thermal spray owing to the compact and less porous morphology. It is concluded that plasma arc sprayed Zn coating is better than arc thermal spray process.

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Design of an Arc Current Controller for Arc Interruption

  • Kang, Chang-Soo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.9
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    • pp.109-113
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    • 2007
  • In this paper, an arc current controller was designed for the interruption of arc fault currents occurred in a low voltage network. Arc in an electrical network represents the characteristics of low current, high impedance, and high frequency. Conventional controllers do not have arc current interrupt functions. Thus, an arc current controller was designed for the interruption of arc fault currents.

The Effects of the Arc Pressure Variation on the Penetration by the filler Wire Feed Rate in Pulsed TIG Welding (펄스 TIG용접에서 필러 와이어 송급속도에 따른 아크압력 변동이 용입에 미치는 영향)

  • 조상명;김진우
    • Journal of Welding and Joining
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    • v.22 no.1
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    • pp.71-76
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    • 2004
  • In the standpoint of the arc pressure, the effects of the filler wire feed rate on the penetration was investigated in this study. The pure Ar gas was used as a shield gas and the parameters investigated were the welding current and the filler wire feed rate. By making the experiment on the arc pressure, we could know that the arc pressure was fluctuated as the depth-into-arc of the tungsten rod. Instead of the filler wire, the tungsten rod was supplied into the molten pool to make this experiment. Because the filler wire melted in arc and then we couldn't measure the arc pressure. So, the tungsten rod - the highest melting point - was used. According to the depth-into-arc of the tungsten rod, the arc pressure could be measured by using the manometer. It was proved that the arc pressure got higher as the wire feed rate was slow. It is reported the arc pressure is proportion to welding voltage and the square of welding current. But, in the filler wire TIG welding, we could blow that arc pressure was fluctuated as the depth-into-arc of filler wire was changed. We could measure the arc pressure by the variation of the filler wire feed rate and could verify that it affected bead shape and penetration.

A Study on the Calculating Method of the Heat Input Efficiency in Arcspot Welding (아크 스폿 용접의 입열효율 계산 방법에 관한 연구)

  • Jang, Kyoung-Bok;Cho, Sang-Myoung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.7
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    • pp.1065-1070
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    • 2003
  • In arc spot welding process, the arc is not moving and heat input is concentrated in one spot so that the heat input efficiency of arc is higher than that of GMAW. In other words, the heat input efficiency of arc change during weld time because arc start is done in spot and weld metal is filled. Therefore, the heat input model of arc spot welding should be different from that of general GMAW. In present study, the calculating model of heat input efficiency in arc spot welding was suggested by temperature monitoring near spot in arc spot welding of copper plate. The result showed that the heat input efficiency of arc was changed three times during weld time. The accuracy of calculating method of heat input efficiency was verified by heat transfer analysis of arc spot welding process using finite element method.