• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.106-108
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• 2002

Capacitive current switching test for circuit breaker and load breaker switch requires special attention because, after current interruption, the capacitive load contains an electrical charge and can cause dielectric restrike and re-ignition of the switching devices. therefore dielectric strength of capacitor load bank shall be able to withstand 4Vt (Vt : test voltage) and charging voltage discharged within 1 min. In this paper presents both characteristic of capacitive current switching tests and design of capacitor load bank.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.

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

• Fire Science and Engineering
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• v.34 no.4
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• pp.1-6
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• 2020

In this study, the authors measured voltage and current waveforms in real time during a serial arc discharge. The analysis results of the arc discharge radiation patterns exhibited intermittent discharge, arc growth, creation of a heat generating area, occurrence of plume, and formation of a red heat area, which proceeded in that order. When the serial arc discharge was introduced, the current and voltage waveforms exhibited periodicity as sine waves. It was also observed that a restriking transient voltage occurred when the waveform changed from positive (+) to negative (-) and vice versa. When the discharge proceeded, the amount of heat generated for 1 s and 600 s was approximately 0.317 mJ, and 190 mJ, respectively. The duration of the short circuit was approximately 1.66 ms, and in the case of the voltage waveform, it was evident that the electric potential increased to 49.9 V in the same cycle. Furthermore, when the discharge proceeded, the effective value (RMS value) of the current was approximately 1.72 A with a maximum current of approximately 2.53 A, whereas the effective value of the voltage was approximately 42.8 V with a maximum of approximately 208 V.