• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.9
• /
• pp.205-213
• /
• 2003

This study describes the mathematical equation of drawdown test model and introduces the experimental test apparatus and procedure to estimate the desorption rate ratio of a filter. The characteristics of a hydraulic filtration system of drawdown test were demonstrated by numerical simulation for various properties of filters and operation conditions. Experiments for three kinds of fuel filters were conducted according to the proposed test method. And the test results of desorption rate ratio were compared with those values anticipated in precedent multipass filtration tests. Experimental results revealed the validation of drawdown test method proposed in this study. Domestic fuel filter yielded high desorption rate ratio comparing with other foreign products, which means that the Beta ratio decreases a lot during the test. The results also showed that filtration system model could be developed including desorption rate ratio to estimate the variable Beta ratio in service life.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.842-844
• /
• 2004

The Back Up Breaker and Making Switch are very important equipments for the short circuit test facility, and contacts are the most important parts of the above switches. There are very many kind of contacts according to switches characteristic and should be done the verification test before use, especially development contacts. This study describes the class of switches, arc chute, material of whole contacts and essential test for verification. The essential test for verification are dielectric test, mechanical operation test, short-time withstand current test, load current breaking test, and short-circuit making current test etc.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.11B no.4
• /
• pp.180-184
• /
• 2001

The high operation frequency mainly reduces transformer volume in the power supply. A high frequency and high voltage pulse transformer is designed, fabricated, and tested. Switching frequency of the transformer is 100 kHz. Input and output voltages of the transformer are 250 V and 4 kV, respectively. Normal operation power of the transformer is 3 kW. Maximum volume of the transformer is 400 $cm^3$. The power density is thus 7.5 W/$cm^3$. The transformer will be installed in a metal box that has nominal operation temperature of 85 degree centigrade. The transformer and other high voltage components in the box will be molded with Silicon RTV(Room Temperature Vulcaniza) that has a very low thermal conductivity. Procedure of design and test results are discussed. Analytical as well as experimental results of varous paramters such as transformer loss, leakage inductance, distributed capacitance are also discussed. In addition, thermal analysis results from ANSYS code for three different operation conditions are discussed.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.904-909
• /
• 2011

The development of train control system shall operate a series of processes like system designing, system production and system performance evaluation as a result of various requirements analysis presented in operation rules, operating guidelines for railway organizations etc, notified by the nation. Therefore, considering operation conditions, operation plan, linkage to railway network etc, the major document like system functional specifications, system development specifications, system test plans etc must be drawn up. In this paper we classify system operating scenarios required to prepare for system standard specification and system performance evaluation report of CBTC system for urban subways supporting unmanned automatic operation, and adjust each of the operating status.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.2
• /
• pp.32-42
• /
• 1998

Lean burn gasoline engine is recognized as a promising way to meet better fuel economy. Lean burn engine is classified into port injection and direct injection(DI), DI is more active technique for improving fuel economy with ultra-lean operation, Nowadays, port injected lean burn engine has been produced by many Japan maker. Also, DI engine is also possible for production owing to improvement in control technique of spray, flow air fuel ratio. DI engine uses either homogeneous stoichiometric mixture or stratified mixture by controlling injection timing to be early or late respectively. HM(homogeneous mixture) is worse than SM(stratified mixture) in view of ultra-lean operation in partical load and Nox reducion by using EGR control. But, HM has advanteges in cold starting and emission reduction during transient operation, This paper describes experimental variables and bench test results of HM GDI engine.

• Journal of Biosystems Engineering
• /
• v.35 no.3
• /
• pp.206-213
• /
• 2010

The purpose of this study is to analyze musculoskeletal injuries in combine harvesting operation using a digital human model. In order to analyze problems in combine harvesting operation, the operations were broken into 5 work processes and then we preformed ergonomic and biomechanical analyses such as RULA test, Comfort Assessment and joint kinetic analysis for the each process. As a result, there was a clear need to change the combine operating environment, as the RULA score ranged from 4 to 7. In addition, we could find two major musculoskeletal injury factors which are the standing posture with upperbody forward tilting and inappropriate location of operating levers.

• Proceedings of the KIEE Conference
• /
• 2006.11a
• /
• pp.30-32
• /
• 2006

New building, reinforcement, maintenance and test of power equipments are always necessary in a power system. Our power system is getting old and the total power capacity is also getting large, so power equipment outages are getting often. Power euipment outages make less margine for a stable condition of a power system operation. Therefore, through overviews and countermeasures against the outage should be made in order to be in a stable operational conditions during the outage. We have too many outages over 300 per month in our power system. So, we can't have enough time to study our power system and to make countermeasures without a helping program. This program is designed to give various and appropriate informations necessary for an outage scheduling. By applying this program, we can raise the job efficiency high and spare the time spent. So we can afford to do through system studies and make good countermeasures. I think this program can contribute greately to power system stable operation.

• Journal of the Korean Society for Railway
• /
• v.8 no.5
• /
• pp.477-482
• /
• 2005

Through a year's commercial operation, Korea High Speed Railway has solved defectives from several breakages at the beginning and is going into the stage of stable operation. Among issues, wheel wear becomes a matter of primary concerns in view of vehicle's stability and maintenance. It was understood as above that wear status has been improved in the test by which railway system including vehicles and tracks was stabilized during a year's commercial operation, comparing to that with excessive wear in the trial operation prior to opening to the public. To make out wheel's wear status and characteristics of equivalent conicity at present when the service has been introduced a year ago and the average cumulative mileage of vehicles reach almost 500,000km, wheel's wear types were analyzed with the current vehicles in service.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1963-1964
• /
• 2008

Scan design is a structured design-for-testability technique in which flip-flops are re-designed so that the flip-flops are chained in shift registers. We propose a new technique to re-design about clock operation. This technique propose about low power operation of scan clock and saved time of test operation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1999.11a
• /
• pp.228-233
• /
• 1999

In this paper we develop an electronic starter circuit that is suitable for Neon sign operation of switch-start fluorescent lamps. The developed starter enable single pulse ignition of fluorescent lamp at the peak point of preheating current, irrespective of the position of the Tum-On signal. This is possible due to the sequential operation of two transistors different in their operation characteristics and a diode operation characteristic. The switching endurance test using this starter has been carried for more than 3000 hours for a single switch-start on a severe blinking condition of preheating of 0.1s and of successive lighting interval of 0.1s.