• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.242-243
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• 2010

This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torch. Series resonant half-bridge topology is presented to be a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. The plasma torch rated for 3MW, 2kA and having the physical size of 1m long is selected to be a high enthalpy source in waste disposal system. The steady-state and transient operations of plasma torch are simulated. The parameters of Cassie-Mary arc model are calculated based on 3D magneto-hydrodynamic simulations. Circuit simulation waveform shows that the ripple of arc current can be maintained within ${\pm}10%$ of its rated value under the existence of load disturbance. This power conversion configuration provides high enough ignition voltage around 5KA during ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance plasma torch system.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1496-1497
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• 2007

This paper deals with the power system development of an arc plasma torch for current control and arc initiation. For stable output of a plasma torch, there are ways of supplying gas suitably, a plasma torch initiation and control system which can control desired output. The design of plasma torch is form of modified Huels type which has narrow downstream. This paper we product suitable feeder of power system and we can control stably in considering many work conditions.

• Convergence Security Journal
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• v.22 no.4
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• pp.129-133
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• 2022

Deep learning frameworks are still evolving, and there are various frameworks. Typical deep learning frameworks include TensorFlow, PyTorch, and Keras. The Deepram framework utilizes optimization models in image classification through image learning. In this paper, we use the TensorFlow and PyTorch frameworks, which are most widely used in the deep learning image recognition field, to proceed with image learning, and compare and analyze the results derived in this process to know the optimized framework. was made.

• Journal of Welding and Joining
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• v.25 no.2
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• pp.49-54
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• 2007

Since the wall thickness can be up to 6" or greater, welds must be made in many layers, each layer containing several passes. However, the welding time for the conventional welding processes such as SAW(Submerged Arc Welding) and FCAW(Flux Cored Arc Welding) can be required many hours. The aim of this paper is to develop a high speed welding system with multi-torch and laser vision sensor for increasing the production speed on the line and to remove the need for the operator so that the system can run automatically for the complete multi-torch multi-layer weld. It was shown that the developed laser vision sensor and analysis of arc blow for multi-torch were effective for multi-pass seam tracking and stable arc. A new automated multi-torch welding systems for thick wall applications has been proved in several production lines.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.92-101
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• 1997

The purpose of this welding process of the exclusive welding-machine using welding torch-rotation type is to develop a mechanism which can solve the problem of twisting of welding wires and cables. The technique was developed by revising the torch position and smooth controlling of both the normal and reverse rotation. Some of the advantages of using the torch-rotation type apply to the work-rotation technique are the practical uses of increased work space and link work with the factory automation system. Do apply the welding process, I designed and made a special unit so called torch part in order to solve the problems of kinematical. And I made a control panel which can manipulate the progress of the entire process at the work shop. Even if it will be applied to another kind of axle casing's welding work, this process can be utilized if other sizes of the fixed pin and work part is produced and changed. The development of this exclusive welding-machine could reduce the manpower of skilled welding labor and increase productivity and better quality product in comparison to the handmade product.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.2
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• pp.191-205
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• 1993

In order to compare the strength of soldered joints relative to the various sol dering method, soldering processes were performed using Palladium based ceramo-metal alloy(Bond-on 4)and Nickel-cromium alloy(Vera Bond). The obtained data include difference in strength between presoldering and postsoldering The data also contain difference among postsoldered groups for 3 difference soldering methods(torch, infrared. Oven) The following results were obtained : 1. For postsoldering with Pd alloy, the oven-using group showed the highest strength while the difference in strength between the torch-using group and the infrared machine group was negligible. 2. For Pd alloy with the torch method, postsoldering resulted in the higher strength than presoldering. 3. There was a negligible difference in strength between presoldering and postsoldering when Ni-Cr alloy with torch method is used. 4. Through microscopic study of the fractured surfaces, the torch-using group showed more porosity than both the oven-using and the infrared machine groups. 5. In terms of fracturing patterns, the oven-using group showed adhesive failure while both the torch and the infrared machine groups showed cohesive failure and cohesive-adhesive failure.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.6
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• pp.791-799
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• 1999

The purpose of this study was to investigate the displacements of cast framework by torch soldering and electric soldering techniques. Specimen had two cylinders and connecting bar that had sectioned with 0.3mm gap at mid point. 10 of total specimens were divided into two groups. In torch soldered group, soldering investment block was made and conventional torch solder-ing procedure was carried out. In electric soldered group, electric soldering was carried out on the master cast without soldering investment block by using electric soldering machine(Dentapunkt DP 7, Kulzer, Germany) After soldering procedure, three dimensional coordinates of two centroids of each cylinder were measured by three dimensional coordinate measuring machine. The intercentroidal displacement and global displacement were calculated and then, these values were compared and evaluated. The results were obtained as follows: 1. Intercentroidal distances of specimens decreased after both soldering procedures, and the decrease in intercentroidal distance was greater for torch soldered group than for electric soldered group 2. Global displacements of torch soldered group were greater than those of electric soldered group.

• Journal of the Korean Society of Visualization
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• v.8 no.1
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• pp.19-24
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• 2010

Five different size of orifice were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The initial flame development and flame propagation were analyzed by the mass burned fraction and combustion enhancement rate. The combustion pressures were measured to calculate the mass burned fractions and the combustion enhancement rates. In addition, the flame propagations were visualized by the shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burned fraction were increased when using the torch-ignition device. The combustion enhancement rates of torch-ignition cases were improved in comparison with conventional spark ignition. Finally, the visualization results showed that the torch-ignition induced faster burn than conventional spark ignition due to the earlier transition to turbulent flame and larger flame surface, during the initial stage.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.48-53
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• 2003

The high temperature melting test for nonflammable wastes using a plasma torch was conducted. The AP-200L hollow cathode type plasma torch was installed at the pilot plasma melting furnace in NETEC. The surrogates were prepared to simulate concrete, soil and their mixture with steel. The experimental conditions such as feeding rate, the distance between melts surface and torch nozzle, torch rotation speed, gas flow rate and pressure in the furnace were decided. Basic parameters such as temperatures of cooling waters, off-gas and torch power were measured. The vitrified samples were analyzed by SEM/EDS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3074-3079
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• 2009

Efficient energy use becomes necessary since energy consumption has dramatically been increasing due to continuous economic development and population growth. In particular, high efficient vacuum glazing needs to be introduced to buildings where enormous energy loss occurs through windows and has been rarely used yet due to its high price and performance. Therefore, in this study, torch for glass welding was developed with CFD(Computational Fluid Dynamics) and experiments. Torch shape, nozzle diameter, nozzle arrangement etc. were mainly optimized and hydrogen-oxygen mixed gas fuels the torch. Finally, glass welding with the developed torch has been successful, showing that it can be used to develop economic vacuum glazing.