• Journal of Welding and Joining
• /
• v.16 no.6
• /
• pp.52-58
• /
• 1998

The effect of Si content in welding wires on th arc stability was investigate, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing Si content, average arcing time and average short circuit time were increased. Therefore, droplet transfer frequency was decreased, due to the increase of arcing time and peak current at the moment of arc-reiginition was increased, due to the increase of short circuit time. In the region of spray transfer, the fluctuations of arc current and arc voltage was the most stable in wire with Si content of about 00.60 wt.%.

• Journal of Welding and Joining
• /
• v.17 no.1
• /
• pp.55-61
• /
• 1999

The effect of S content in welding wires on the arc stability was investigated, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing S content, average arcing time and average short circuit time were decreased. Therefore, droplet transfer frequency was increased, due to the reduction of arcing time and peak current at the moment of arc-reiginition was decreased, due to the decrease of short circuit time. In the region of spray transfer, the fluctuation degree of arc current and arc voltage became more stable, with increasing S content.

• Journal of Welding and Joining
• /
• v.15 no.6
• /
• pp.41-48
• /
• 1997

For analyzing the characteristics of arc welding processes, an algorithm is necessary to determine the metal transfer mode, arc stability and weld quality. In this study, the weight of spatter during welding was selected for determining the arc stability, which is very relevant to the occurrence of spatter. Weld spatter occurs mainly at the moment when the short circuit is formed and also when it is broken causing the arc to restrike. Based on this fact, the arc stability can be determined by finding the suitable parameters of welding current and arc voltage which influence the weight of spatter. Through various welding experiments, the peak current, the arcing time, the short circuit time, the current and its slope at the start of short circuit were found mainly to influence the weight of spatter. For the convenient usage, an index was proposed by combining all these parameters. It was found that the index is very effective for determining the arc stability.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.2
• /
• pp.100-105
• /
• 2022

This paper applies the arc detection algorithm to prevent the false detection in photo voltaic series arc detection circuit, which is required not only to detect the series arc quickly, but also not falsely detect the arc for the non-arc noise. For this purpose, this study proposes a rapid and preventive false detection method of single peak noise and short noise signals. First, to prevent false detection by single peak noise, Discrete wavelet transform (DWT)-based characteristic parameters are applied to determine the shape and the amplitude of the noise. In addition, arc fault detection within a few milliseconds is performed with the DWT iterative algorithm to quickly prevent false detection for short noise signals, considering the continuity of serial arc noise. Thus, the method operates not only to detect series arc, but also to avoid false arc detection for peak and short noises. The proposed algorithm is applied to real-time serial arc detection circuit based on the TMS320F28335 DSP. The serial arc detection and peak noise filtering performances are verified in the built simulated arc test facility. Furthermore, the filtering performance of short noise generated through DC switch operation is confirmed.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.8 s.179
• /
• pp.1885-1898
• /
• 2000

Welding quality is closely related to the arc state. So, it is very important to estimate the arc state in real time. In the short circuit transfer region of CO2 are welding, the spatter , as it is well known, is mainly generated on an instance of short circuit or on an instance that the are is ignited after short circuit, or on the cases of an instantaneous short circuit. If the short circuit period or the arc time is irregular, the spatter is generated more than it is regular. Thus there is a close relationship of the amount of the spatter generation with the arc stability. In this paper, to develop the index for estimating the arc stability in short circuit transfer range Of CO2 arc welding, the welding current and are voltage waveforms were measured and the spatter generated was captured and measured. The correlation analysis of the measured amount of the spatter with the factors (the components and the standard deviations of the components) was performed, and the factors that have a considerable influence on the spatter generation among all factors were selected. And some cases of models consisted of the factors were presented, and a mathematical index model which can make an estimation the amount of the spatter from these models with multiple regression analysis. Also, it was compared how much the amount of the spatter generated under the selected welding conditions do these index models fit, and the index model to estimate the arc stability which represent the spatter generation most appropriately was developed

• Journal of Welding and Joining
• /
• v.23 no.5
• /
• pp.14-19
• /
• 2005

In high speed $CO_2$ welding, it has been blown to produce no sound bead with undercut or humping bead. In this study welding phenomena through synchronized high speed camera and output welding voltage and current waveform has been analyzed. For the purpose to improve a welding bead, effect of short circuit current rise slope has been examined. With commercial power source it was produced no sound bead by instantaneous short circuit, long arc period and stubbing at welding speed 2.5mm/min Humping bead or undercut were showed by instantaneous short circuit and long arc period. Also, the weld bead was not formed during the long short circuit period after stubbing start and long arc extinguishment period after wire sticking by failure of arc regeneration, because the droplet was not transferred to weld pool. With increasing short circuit current rise slope the frequency of stubbing was decreased and the normal short circuit rate was increased. A control of short circuit current rise slope was effective factor in high speed welding.

• Journal of Welding and Joining
• /
• v.16 no.3
• /
• pp.95-101
• /
• 1998

Waveforms of $CO_2$ gas shielded arc welding in short circuit transfer mode was studied with the waveform analysis program, which can calculate various waveform factors such as number of short circuit event, mean and standard deviation of short circuit time and arc time. The calculated values of these factors were correlated independently or in combination with the spatter generation rate to figure out the most reliable index for evaluating spatter generation and further for arc stability. As a result this study, it was confirmed that the spatter generation tends to decrease with the increase of short circuit frequency. Further to this, it was also found that as the short circuit frequency increases the short circuit event becomes more uniform resulting in the decrease of standard deviations ($\sigma$values) of short circuit time and arc time. This result demonstrated that these factors are strongly correlated with each other and thus any one of these factors can be used for the evaluation index. In the discussion, however, short circuit frequency was proposed for the most practical index in evaluating the arc stability of short circuit transfer mode since it is the one which could be monitored in-process condition without any complex caculation process.

• Journal of the Korean Society of Safety
• /
• v.27 no.4
• /
• pp.38-42
• /
• 2012

This paper describes electrical fire on residential environment such as apartment and detached house caused by defect of interior wiring. We carried out experimental study on short circuit characteristics by the interior wiring length. We were measured arc current, arc energy and interrupting time of earth leakage current circuit breaker(ELB), when an interior wiring break out short circuit in residential environment. From the experiment results, the longer of the interior wiring, the magnitude of arc current decreased and the interrupting time of ELB increased. When applied the A maker's ELB, the strength of arc current and interrupting time of ELB was 254 A and 245 ms respectively at 30 m interior wiring length. In 3 m interior wiring length, arc current and interrupting time was 716 A and 4.24 ms respectively. Arc energy was dependent on the magnitude of arc current and the interrupting time of ELB, the longer the interrupting time, arc energy increasing. In this paper, minimum arc energy was 277 J using C maker's ELB and 3 m interior wiring length(arc current 283 A, interrupting time of breaker 6.28 ms). Therefore in the residential environment, short circuit caused by defect of the interior wiring lead to electrical fire.

• Journal of Welding and Joining
• /
• v.19 no.6
• /
• pp.630-635
• /
• 2001

The characteristics of spatter generation in the short circuit transfer region of $CO_2$ welding was investigated. Spatteriing phenomena could be classified into three types : Type I generated due to the abrupt increase of arc voltage in arcing duration. Type II by the gas ejection from molten metal and Type III generated by the arc instability at the moment of arc re-ignition just after short circuiting. Main observed types were dependent on the chemical composition of welding wires. The case of YCW12 wires was mainly composed of spatters generated by Type l and Type II, while most, spatters in YCW11 wires were generated by Type II and Type III.

• Journal of Welding and Joining
• /
• v.8 no.1
• /
• pp.31-42
• /
• 1990

Arc must be stable during welding first of all other factors for obtaining sound weldment, especially in the automation of welding process. Arc stability is somewhat sophisticated phenomenon which is not clearly defined yet. In consumable electrode welding, the voltage and current variation due to metal transfer enables to assess arc stability. Recently, statistical analyses of the voltage and current waveform factors are performed to assess the degress of arc stability which is assessed and controlled by operator's own experience by now. But, considering the increasing need and the trend of automation of welding process, it is necessary to monitor arc stability in real-time. In this sutdy, the modified stability index composed of two voltage and current wvaeform factors (arc time and short circuit time) reduced from four factors (arc time, short circuit time, average arc current and average short circuit current) in Mita's index by the welding electrical circuit modeling is proposed and verified by experiments to be well estimating arc stability in the static sense. Also, the recursive calculation form estimating present arc stability in the dynamic sense is developed for real-time estimation. The results of applying the recursive index during welding show good estimation of arc stability in real-time. Therefore, the results of this study offers the mean for real-time control arc stability.