• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.118-122
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• 2000

Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. For composition of this technology, the development of system with high speed and high resolution is needed. At start point and end position vibration must be repressed on this system for composition of position control. This vibration is arisen nose, is increased setting time, is reduced accuracy. Especially, repressed for the lead with high speed. The small actuator with high speed and high resolution is need to repression against this residual vibration. This actuator is, for example, piezo actuator, piezoelectric material that converting from electronic signal to mechanical force is adequate material, beacause of control of control to position and force. In this study, piezo electric material is used to actuator, ultra precision positioning apparatus with stage of hinge structure is designed, simulation is performed, control performance is tested by producing apparatus. For easy usage and stability in industrial field, we perform to simulation and to position control test by digital PID controller.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.699-704
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• 2005

In the station of the railway and the subway various illumination equipment and a general power equipment for a passenger convenience, the signal equipment and the communication equipment which is necessary to the train operation provided. At the all of like this equipment from the electric room which is established in each station by changing from high voltage to low voltage and it supplies from the illumination transformer, the power transformer and the signal transformer. If it supplies to the equipment from the high voltage to the low voltage, it must be established to contact protection device in between the high voltage coil and the low voltage coil. Also it must do the grounding faulting device at the low voltage lines, the earthing devices at apparatus for the protection of an electric shock and an electric fire by the electric relation law. Compared the related regulations between the facilities which require protective functions such as grounding fault or earthing in public utilities like subway stations, and the facilities which do not require line earthing or protective functions such as electricity supplied for signalling the train. Also, will describe a countermeasure for the accident from a grounding fault.

• Journal of the Korea Computer Industry Society
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• v.5 no.2
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• pp.217-226
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• 2004

This paper proposes the electric stimulus tactile apparatus system(TESTAS) loaded on the haptic interface using ultrasonic motors (USMs) To touch the virtual object like wall in graphic, the 6 DOF haptic interface provides force feedback to users as if it is real. But the case of sharp virtual object like a puncture, it could not provided the sense of pain, but only the reaction-force. After the TESTAS had been loaded on this haptic interface, it could provide not only the force but also the pain to users. In this way, when users take the haptic and tactile informations at the same time, they easily have a correct understanding of virtual object.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.236-241
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• 2017

Electrohydraulic forming is a high-speed forming process that deforms a blank using electric discharge in liquid. When high voltage is discharged in the water, a shock wave is propagated from the tip of the electrodes to the blank, causing the blank to be deformed into the die. Electrohydraulic forming has many advantages including improved formability and reduced bouncing effect and springback. The objective of this paper was to conduct a feasibility study to identify the electrohydraulic effect. An electrohydraulic forming apparatus was developed and experiments were carried out. The results of the experiment showed that the developed apparatus had sufficient energy to deform the blank into the die. Using the hole to emit residual air in the die was more effective than using the vacuum pump in terms of saving on experiment time.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1317-1319
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• 1997

This paper is to study and develope a measurement apparatus for ferroelectricity. The apparatus consists of wave generation part, high voltage amplifier part, measurement part, data acquisition part and the related controll circuits. Single or double excitation wave is digitalized and sent to the external RAM of wave generation part by personal computer. These datas saved in the RAM are converted to analog excitation wave through D/A converter. The frequency of excitation wave is depend on the read-out speed of the RAM by clock pulse. Such generated wave is applied to high voltage amplifier as a input voltage. The output of high voltage amplifier is applied to ferroelectrics and the response is obtained from the charge amplifier of measurement part. The response is sampled and converted to digital datas through AID converter. These digital datas are automatically saved in the external RAM of acquisition part. The computer takes the digital datas and calculates the electric displacement D, the electric field and the dielectric constant $\varepsilon$. We tested for PZT ceramic sample and could observed the D-E hysteresis lops and ${\varepsilon}_s$-E hysteresis loops with good forms.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1498-1499
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• 2007

In general, ALT can be used to expect the lifetime of electric machines and accelerated stress testing(AST) is used to evaluate the residual life of insulation system. In this paper, a method to design the accelerated life testing(ALT) for reliability qualification of electrical apparatus is represented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.203-206
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• 2001

Since th three sides of korea peninsula are surrounded by the sea, electric apparatus are greatly contaminated by the salt generated by the typhoon, seasonal wind, sea wind and sea fog. This contamination causes electric power apparatus to fail. Thus in this paper, we investigated to influence upon electrical properties of outdoor insulators with non-uniformity contamination in the experimental condition because The contamination of outdoor insulator highly depended wind property In the service condition, insulator was not uniformly contaminated. From the flashover test for the 254 mm suspension insulator, we could determine the influence non-uniform contamination on the electrical property of insulators. Through the experiment, we convinced to occur flashover from non-uniform contamination region of outdoor insulator. Contaminated area and pattern has a close relationship with the electrical properties of outdoor insulator.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.435-437
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• 2003

Recently, as the road capacity reaches the limit and environmental problems becomes serious, there is gradually increased a need for railroad vehicles that are environment-friendly and have time regularity, reliability and safety. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. We developed the hardware and software of the measurement system for on-line test and evaluation of korean hish speed train. The software controls the hardware of the measurement data and acts as interface between users and the system hardware. In this paper, we is studied for electric apparatus performance of railway vehicle using sensor. In order to this test is developed signal conversion system. Using this system, we obtained important result for pantograph voltage, battery voltage, axle speed, and running speed.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.217-219
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• 2003

This paper, as a preliminary study, presents the important consideration in laboratory planning and designing 4.2MV impulse voltage generator(IVG), which enable to test and evaluate the UHV dielectric performance of power electric apparatus up to 765kV-class. To fix and confirm the kinds of loads and their capacities to be tested by KERI hereafter, wide investigation and an analysis of test objects, especially heavy electric apparatus of Korea, according to their ratings and test voltages have been conducted. With the special consideration concerning other matters in designing of 4.2MV IVG have been described with the practical examples and references.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1208-1210
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• 1999

Design & operation power systems for meeting increase of electric power demand is becoming more difficult and complex. Some of limitations of conventional technology can be broken through by the application of superconductivity technology. This paper presents a new concept & image for the configuration of superconducting power system which has introduced superconducting(SC) generator, cable, transformer, fault current limiter(SFCL), SMES, etc. Engineering evaluation of each power apparatus and its assessment of application to power system were conducted. Futhermore, it is pointed that superconducting power system require a new operating condition. This is, SFCL should play a important part of quenching current level coordination to prevent the other superconducting devices from quenching. Its designing & operating condition including SFCL was discussed in viewpoint of quenching current level and insulation coordination of SC coil.