• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.316-320
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• 2008

A light rail transit, using a linear induction motor, is generally composed with reaction plates along railroad track and the three phase primary on the vehicle. This linear induction motor is driven to keep clearance between the primary and the secondary of the ground for preventing any contact. Therefore efficiency and power factor is very low. In addition, the reaction plate installed on the ground throughout entire railway is impossible to keep uniform gap and it may cause system deterioration. In this paper, A rotary-type small-scale model of a linear induction motor for various characteristic analysis is designed. Thrust force, normal force and input current of the model by air-gap variation have been analyzed by using a Finite Element Method (FEM). The effects of air-gap variation on system performance have been considered by analysis results.

• 전기학회논문지
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• 제62권4호
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• pp.577-583
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• 2013

We have analyzed influence of potential rise in negative bus, which caused by decrease of power feeding line insulation, upon protecting method of DC ground protection device which detecting potential rise between negative bus and ground in order to detect ground fault in the rubber wheel system. For this purpose, we proposed negative potential equation between negative bus and ground and calculated negative potential according to system condition changes by estimating power feeding line insulation changes in steel wheel system and rubber wheel system, and equalizing DC power feeding system when ground fault occurred. Also, in order to estimate negative potential of real system, we modeled the rubber wheel system, and simulated normal status, grounding fault occurrence and power feeding line insulation changes. In normal status, negative potential did not rise significantly regardless of vehicle operation. When ground fault occurred, negative potential rose up over 300V regardless of fault resistance. However, we also observed that negative potential rose when power feeding line insulation dropped down under $1M{\Omega}$. In conclusion, our result shows that in case of rubber wheel system unlike steel wheel system, relay will be prevented maloperation and insulation status observation can be ensured when ground over voltage relay will be set 200V ~ 300V.

• 실천공학교육논문지
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• 제8권2호
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• pp.103-109
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• 2016

철도 차량의 정상적 운행을 위한 정비 작업이 안전하게 이루어지기 위해서는 실제 열차 정비 환경을 직접 겪어 보며 경험을 쌓고 실무능력을 키워나가야 하지만 정비 절차에 따르는 운영상의 문제로 실제 정비를 경험하는 정비교육훈련은 어려운 상황이다. 그렇기 때문에 실제와 최대한 유사한 환경에서 체험하는 시뮬레이션을 열차 정비 교육에 적용한다면 안전한 상황에서 실제 정비 업무에 대한 지식과 경험을 쌓을 수 있고, 운영상의 교육훈련비용도 절감할 수 있다. 현재 국내와 해외에서 운용되고 있는 철도 분야의 시뮬레이션 프로그램의 경우 열차운행 위주의 교육훈련으로 설계 되어 있고, 정비관련 및 유지보수 내용에 대한 묘사는 부족한 상황이다. 본 연구에서는 열차 정비의 교육효과를 위해 교육공학이론 중 내용요소전시 이론, 상황학습 이론, 문제 중심 학습이론을 고찰하는 선행연구를 통해 열차 정비 교육 시뮬레이션을 설계한다.

• IEIE Transactions on Smart Processing and Computing
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• 제4권4호
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• pp.291-296
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• 2015

This paper describes the design of a high-speed comparator for high-speed automatic test equipment (ATE). The normal comparator block, which compares the detected signal from the device under test (DUT) to the reference signal from an internal digital-to-analog converter (DAC), is composed of a rail-to-rail first pre-amplifier, a hysteresis amplifier, and a third pre-amplifier and latch for high-speed operation. The proposed continuous comparator handles high-frequency signals up to 800MHz and a wide range of input signals (0~5V). Also, to compare the differences of both common signals and differential signals between two DUTs, the proposed differential mode comparator exploits one differential difference amplifier (DDA) as a pre-amplifier in the comparator, while a conventional differential comparator uses three op-amps as a pre-amplifier. The chip was implemented with $0.18{\mu}m$ Bipolar CMOS DEMOS (BCDMOS) technology, can compare signal differences of 5mV, and operates in a frequency range up to 800MHz. The chip area is $0.514mm^2$.

• 한국철도학회논문집
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• 제15권3호
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• pp.224-230
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• 2012

전동차의 집전장치용 주습판은 형태와 재질에 따라 마모현상에 상당한 차이가 있으며 특히, 강수량에 따른 이상마모, 아크에의한 급격한 이상마모는 전차선과 주습판의 수명을 결정하는 주요인자로 작용한다. 본 연구는 현차 실험을 통하여 우수한 전기전도도 및 내아크성을 가진 동계주습판의 마모현상을 정상마모 특성이 관찰된 동계주습판과 우천 시 국부적으로 이상마모 특성이 관찰된 동계주습판에 대하여 강수량, 주행거리 및 주습판의 교환 후 중량을 상호 비교하여 분석하였다. 트라이볼로지적 접근을 통하여 내마모성 등이 우수한 철계습판체의 적용 필요성을 본 실험적 연구를 통하여 제안하였다.

• 한국생산제조학회지
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• 제24권2호
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• pp.203-210
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• 2015

This paper investigates the failure of a car with a 2.5-liter CRDi engine of the Hyundai Company. The failure is caused by intermittent poor acceleration while driving. To analyze the cause, we investigated the air intake volume, the fuel injection, and the air-fuel ratio, which were determined to be normal. The brake switch signal error was discovered while analyzing the function that limits the output of the engine. While investigating the cause, we discovered the corrosion of the pins on the connector of the brake switch. We determined that it was generated by soapy water flowing in the solar film. Therefore, the cause of the failure was the brake switch signal errors. Additionally, we determined that ECM was the normal fail-safe mode that implemented the override device for safety during normal acceleration. Based on these results, further solar film experiments must be conducted to fully elucidate the causes.

• 한국철도학회논문집
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• 제16권3호
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• pp.207-216
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• 2013

콘크리트궤도가 부설된 철도교량 단부의 궤도구성품(레일 및 체결구)에는 교량 단부회전에 의해 상향력 및 압축력과 같은 궤도-교량의 상호작용력이 작용하여 손상 및 성능저하가 유발된다. 이러한 교량의 휨거동에 기인한 단부 궤도의 상호작용에 따른 문제를 해결하고자 본 연구에서는 횡단궤도시스템을 개발하고 그 성능을 입증하였다. 횡단궤도시스템의 구조안정성 검토를 위해 3차원 유한요소해석을 통한 시간이력해석을 실시하고 그 결과를 독일의 성능요구조건 및 관련기준과 비교하였다. 또한, 교량-궤도 상호작용 분석을 위한 시험체를 제작하여 실내시험을 수행하고 횡단궤도시스템의 적용 효과를 평가하였다. 연구결과 횡단궤도시스템의 정, 동적 구조안정성 및 횡단궤도 적용 후 교량 단부 궤도의 상호작용력(레일변위, 레일저부응력 및 체결구 응력)이 크게 저감될 수 있음을 실험적으로 입증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1697-1702
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• 2010

It has been recognized for decades that the spherical bearing which is sliding on curved surface in the intrinsic behavior is optimized for the railway bridge requiring a large slope deflection. However, the spherical bearing is easily corrosived at the PSC girder bridge which is exposed to the outside so the normal function of bridge bearing is not fulfilled fully. It is common that the corrosion is happened at the operating plate of steel bridge bearing and generally it is necessary to replace the bridge bearing after 20~25 years. Accordingly, It costs multi billion dollars for maintenance each year and the necessity of improvement become a issue. Korea Rail Network Authority(KR) suggested to apply the Elastomeric bearing instead of Spherical bearing through the task of construction site of 2006. But the normal Elastomeric bearing is optimized for the Highway bridge so it needs the special consideration to satisfy each design condition required by railway bridge. As the result of examination of Elastomeric bearing at the railway bridge construction site, the stress is decreased by effective dispersion of earthquakes and the maintenance fee is also decreased.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.724-730
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• 2011

A turnout serves to switch train from one line to another. The turnout consists of a Point which is switchs the rail to induce direction, and a Crossing which is cross over two line on the plane surface, and a Lead where is middle section in Point to Crossing. Point machine, consists of a turnout, is important facilities in railway signal, that is safety issue relates in derailment of the train. Recently, train delay and accident frequently occurred because of the turnout include in a point machine trouble of electrical and mechanical. So in order to prevent train accident the research is advanced, install of normal and reverse indication lamp in a point machine, development of adherence detector for sensing the status of adhesion between the stock rails and tongue rails etc. In this paper investigates the problem which is connected with a turnout trouble, include in a point machine, occurrence at the time of train accident, and then proposed to the safety system model in order to prevent the train accident in turnout.

• 한국안전학회지
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• 제17권2호
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• pp.22-31
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• 2002

In present study, the deformation analysis and automotive body repair were analyzed with respect to collision types by case studies. As a result, lots of data for the automobile frame deformation caused by collision were collected and analyzed according to collision types. It was shown from the result that the frame deformation patterns were able to be roughly grouped by collision positions of vehicles. Repair plans of deformed frames could be carried on the measured data. It was shown that the deformed vehicle frames were sufficienty repaired to be normal in driving characteristics from the performance test of repaired vehicles.