• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.4-5
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• 2018

The water proofing sheet of synthetic polymer applies to the purification plant, the wastewater treatment center, the low waterway, the dosing tanks, etc, and when we construct these, we apply the dual waterproof by means of hot air staking welder or extruder. However, the experts skilled in the hot air welding or extruder does not use them, it can be a quality problem. Therefore, in this study, it is the purpose to verify whether the semi-automatic hot air staking welder and automatic extruder that can construct the waterproof sheet is possible in field even if it is not a professional specialist.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.294-303
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• 1999

Resistance spot welding is commonly used for welding products of high quality because of clean welding and short w welding-time. But. conventional spot welders bring about the depreciation of welding products, iuespective of dynamic r resistance characteristics during welding time. This paper discussed dynamic resistance database implementation in t terms of welding performance improvement. On different welding conditions, we compared dynamic resistance, r respectively, about pure iron and Sn-Pb alloy on Copper. Also, it investigated the relation of tensile shear strength and d dynamic resistance in welded workpiece.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1571-1577
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• 2015

A new mixed mode control of constant power and constant current for resistance spot welding inverter is proposed to improve the weld quality. The conventional control scheme adopts constant current or constant power control mode, however, it is not easy to guarantee the high weld quality because of the nonlinear resistance characteristics of the welding point. The proposed method utilizes the nonlinear characteristics by measuring the dynamic resistance in real time. Therefore, it is possible for the welder to be controlled adaptively depending on the welding state. Experimental results show that the proposed control scheme improves the weld quality by 6.8 times compared with the conventional constant current mode control.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1888-1889
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• 2007

The power source of inverter welder stable power of low voltage and high current. Because if shouldn't be, it is caused to spark between the parent metal and the peak. So that, we designed to be base on high frequency transformer and reactor of DC part. Then, we optimized control of PWM, current rising slant, voltage, current, pulse current and 인버터 out-put voltage. Also we designed PCB for EMI and noises.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.154-156
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• 1997

• Proceedings of the KWS Conference
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• v.43
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• pp.46-48
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• 2004

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.161-164
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• 1999

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.399-402
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• 2006

This paper presents a new circuit topology of dc bus line switch-assisted half-bridge soft switching PWM inverter type dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to dc bus line side power semiconductor switching devices fer PWM control scheme and capacitive lossless snubbers. All the active power switches in the half-bridge arm and dc bus lines can achieve ZCS turn-on and ZVS turn-off commutation operation and consequently the total turn-off switching losses can be significantly reduced. As a result, a high switching frequency of using IGBTs can be actually selected more than about 20 kHz. The effectiveness of this new converter topology is proved for low voltage and large current dc-dc power supplies such as arc welder from a practical point of view.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.339-340
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• 2008

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.27-29
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• 1999