• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.26-30
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• 2009

In this paper, a robust model based fault detection for varying temperature is proposed, To develop a robust force estimation model, it needs temperature information because the force sensor's output is affected by a temperature variation. If an EPB system does not include a temperature sensor, the model has a much larger error than an EPB system with a built-in temperature sensor. Therefore, the temperature is estimated by using Ohm's law. The force model is applied with a motor current, battery voltage, operation mode, and the estimated temperature to detect a force sensor's abnormal signal fault. The residual is calculated by comparing the value of the measured force and the estimated force. Fault information is collected by using the output of the evaluated residual with the adaptive thresholds. A proposed robust model based fault detection for varying temperature was verified by HILS (Hardware in the Loop Simulation).

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.365-370
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• 2004

The integration of intelligent devices, devices-level networks, and software into motor control systems can deliver improved diagnostics, fast warnings for increased system reliability, design flexibility, and simplified wiring. Remote access to motor-control information also affords an opportunity for reduced exposure to hazardous voltage and improved personnel safety during startup and trouble-shooting. This paper presents LonWorks fieldbus networked intelligent induction control system architecture. Experimental bed system with two inverter motor driving system for controlling 1.5kW induction motor is configured for LonWorks networked intelligent motor control. In recent years, MCCs have evolved to include component technologies, such as variable-speed drives, solid-state starters, and electronic overload relays. Integration was accomplished through hardwiring to a programmable logic controller (PLC) or distributed control system (DCS). Devicelevel communication networks brought new possibilities for advanced monitoring, control and diagnostics. This LonWorks network offered the opportunity for greatly simplified wiring, eliminating the bundles of control interwiring and corresponding complex interwiring diagrams. An intelligent MCC connected in device level control network proves users with significant new information for preventing or minimizing downtime. This information includes warnings of abnormal operation, identification of trip causes, automated logging of events, and electronic documentation. In order to show the application of the multi-motors control system, the prototype control system is implemented. This paper is the first step to drive multi-motors with serial communication which can satisfy the real time operation using LonWorks network.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1025_1026
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• 2009

This paper introduces the test a rapid pulsed power charging system for pulsed power application. The charger is designed based on three-phase series resonant inverter followed by air cooled step-up transformers. It has many advantages of lower weight, small size and high efficiency compared with large bulky traditional pulse power charging system. To apply 150kJ pulsed power system, detail test was carried out at various condition and its results shows 90% efficiency at full load condition. And additional experiments such as short, open, and self discharging during charging status are performed to verify reliable operation at abnormal condition and it was confirmed that developed capacitor charger showed very reliable operation all over the tests.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.27-34
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• 2007

The rotor faults of induction motors may cause bad effects on the performance of the induction motor. This paper proposes the detecting technique of these faults by analyzing the waveform of the induced current and voltage of search coil using numerical analysis and the experiment. Several defective rotor bars are simulated to analyze the fault conditions-broken bars and high resistance of rotor bars. In order to prove the usefulness of the proposed method, we made an prototype experimental apparatus. The waveform of the induced voltages in search coil has the obvious characteristics and it is easy to differentiate the normal rotor from the abnormal one. The experimental results show that the proposed method is useful to detect the rotor fault conditions.

• Sleep Medicine and Psychophysiology
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• v.1 no.1
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• pp.36-46
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• 1994

The event-related potentials are difined as the changes in voltage that occur at paticular time before, during and after something that happens in the physical world or some psychological processes. The possibilities of clinical applications of ERP are considered because the endogenous potentials such as P3 and contingent negative variation(CNV) are determined by the psychological significance of the stimulus. The P3 is a positive wave that occurs when a subject detects an informative task-relevant stimulus. The P3 amplitude and latency are affected by the various factors as subjective probabilites, stimulus meaning and information transmission. It is suggested that P3 wave is associated with the decision making, cognitive or perceptual closure, memory updating and transfer of information to consciousness etc. Although the intracerebral origin of the P3 wave is not known, the P3 may have multiple intracerebral generators. The CNV is a slow potential shift occuring during the foreperiod, between warning and response signals, in a reaction time experiment. It is related to expectancy, preparation etc. The abnormal findings of P3 wave and CNV in various psychiatric disorders are also discussed.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.29-32
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• 2001

In this paper, the thermal oxidation behaviors and the electrical characteristics of the thermal oxide grown on SiC are discussed. For these studies the oxide layers with various thickness were on SiC in wet $O_2$ or dry $O_2$ at l15$0^{\circ}C$ and the MOS capacitors using the 350$\AA$ gate oxide grown in wet $O_2$ were fabricated and electrically characterized. It was found from the experimental results that the oxidation rate of SiC with the Si-face and with the carbon-face were about 10% and 50% of oxidation rate of Si. The C-V measurement results of the SiC oxide showed abnormal hysterisis properties which had ever been not observed for the Si oxide. And the hysterisis behavior was seen more significant when initial bias voltage was more negative or more positive. The hysterisis property of the SiC oxide was believed to be due the substantial amount of the deep level traps to exist at the interface between the oxide and the SiC substrate. The leakage of the SiC oxide was found to be one order larger than the Si oxide, but the breakdown strength was almost equal to that of the Si oxide.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.113-117
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• 2006

This study presents analysis of fire hazard of electrical heating pad. In order to analyze fire hazard fire experimental and flammability experiment is conducted. The fire experiment is conducted to simulate normal condition and abnormal condition such as breakdown of thermostat. Vertical burning test(UL 94) is conducted for the fire retardant experiment. Kinds of electric heating pad used for experiment are electric mat, fabric pad, vinyl pad. The results show that fire hazard is high in case of breakdown of thermostat with the rating voltage supply. And Material of electric heating pad has not fire retardant performance.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1067-1068
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• 2008

The Operation of high speed train in year 2004 bring about a great change in railroad industry. Especially in railroad construction field we have acquired great Know-how. And up to now we are building up operation skills. But the high speed train system are totally imported, so it is necessary to investigate some of the equipment based on our own environment. In case of Toughened Glass Stem Insulator, we don't have any application case in domestic and limited in abroad. So there must be some characteristic estimation. The estimation was made in three different ways. First electrical field cause, Second physical field cause and finally in circumstance cause. In Electrical field cause, amplitude and number of time for abnormal peak voltage data are collected. And in physical field cause, amplitude and trend of vibration in to the insulator are examined. And I circumstance cause, possibility of flying gravel and ice clod are investigated. Through this basic data suitability for Toughened Glass Stem Insulator using in domestic will be accumulated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.141-148
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• 2017

Recently, localized heavy rain storms have been occurring frequently due to global warming, and it is difficult to shield a large number of facilities against disaster with limited manpower. The unmanned water treatment system uses five senses to analyze various judgment criteria, which are set according to field situations such as machine vibrations, the temperature of bearings, the sound of the operating machines, and the hydraulic pressure, current, and voltage of the hydraulic floodgates. It thus judges normal or abnormal operation status and conducts unmanned control of such machines. It automatically applies a system to the interruption of communications and therefore improves the reliability of its unmanned irrigation facilities. It maximizes the operational efficiency of managers responsible for various fields, enabling them to discharge water before the situation escalates to a crisis within the golden time, and to protect against damage to humans and property.

• Journal of the Korean institute of surface engineering
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• v.47 no.4
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• pp.155-161
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• 2014

The present work is concerned with the formation behavior of anodic oxide films on Al7075 alloy under a galvanostatic condition in 20 vol.% sulfuric acid solution. The formation behaviour of anodic oxide films was studied by the analyses of voltage-time curves and observations of colors, morphologies and thicknesses of anodic films with anodization time. Hardness of the anodic oxide films was also measured with anodization time and at different positions in the anodic films. Six different stages were observed with anodiziation time : barrier layer formation (stage I), pore formation (stage II), growth of porous films (stage III), abnormal rapid oxide growth (stage IV), growth of non-uniform oxide films (stage V) and breakdown of the thick oxide films under high anodic voltages (stage VI). Hardness of the anodic oxide films appeared to decrease with increasing anodization time and with the position towards the outer surface. This work provides useful information about the thickness, uniformity, imperfections and hardness distribution of the anodic oxide films formed on Al7075 alloy in sulfuric acid solution.