• Proceedings of the KSR Conference
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• 2007.11a
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• pp.26-29
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• 2007

In Korean Electric Motor Unit(EMU) industry, the government should lead and drive the development of the product-oriented fundamental technologies(for example, Life Cycle Assessment, Environmental Labelling, Ecodesign, Eco-efficiency etc.) for the EMU. International Railway Union(UIC) establish UIC code 345: Environmental specification and it is based on using the product-oriented fundamental technologies. And also many foreign railway related companies already shown their environmental performance using the product-oriented fundamental technologies So, in Korean situation, it is important that let the EMU industrial player understand the importance of the product-oriented fundamental technology for the EMU and clarify who drive the development of the product-oriented fundamental technology for the EMU and what the type of driving forces.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.22-25
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• 2007

Industry faces a considerable challenge to meet the high demand for reduced impacts and improved environmental performance. With this current stream, railway industry launched a systematic scheme for environmental friendly EMU and its system. An assessment tool which evaluate the environmental impacts of the product through its entire life cycle has been developed. The next step to environmentally sound and sustainable product design, shortly ECODESIGN has come to be essential and necessary as well. Ecodesign requires to identify possible stakeholder requirements first. The paper illustrates way how to define stakeholder requirements in terms of environment and shows approach linking stakeholder requirements to environmental parameters.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.329-335
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• 2003

This study is on a experiment which shows to defrost automatically on the optimum time regardless of defrosting method. The result shows that the more defrost layers increase in fin tubes of evaporation, the less the section of the circulating air reduce. Thickness of the frost formation increases, so a pressure difference of ventilation increase, as a result automatic defrosting system sets the time COP drops suddenly up optimum time. Automatical defrosting system can find out the initial related current of evaporator fan motor and the value of load current in the optimum time. And it sets defrosting time, evaporating temperature, and temperature in refrigerator up system requiring value. Consequence of this experiment is that energy consumption with defrost load gets effect of reduction of eleven percent per 25.4 hours compared with common defrosting.

• Tribology and Lubricants
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• v.15 no.1
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• pp.17-23
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• 1999

A Gerotor hydraulic motor is a planar mechanism consisting of a pair of rotors one of which encloses another rotor. The motion of the inner-rotor relative to the outer-rotor is produced by the pressure difference between the adjacent chambers. A design method of inner-rotor tooth profile using unit tangential vectors is presented in this work. Based on the relationships derived, the influence of the eccentricity of inner-rotor and the radius of circular arc tooth on the flow rate, torque and curvatures were investigated. It was shown that the flow rate and mean torque is proportional to eccentricity, but inversely proportional to the radius of circular arc teeth. Also, the maximum value of the equivalent curvature is increased as the eccentricity and the radius of circular arc teeth increased.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.211-212
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• 2008

There are many new technologies for EMU to secure the facilities' safety/validity and maintenance/economical efficiency and technologic competitiveness. For example, now the EMU is using the blending brake technology with electric brake and pneumatic brake and carrying the various performances such as jerk limitation, variable load and blending brake to stop the motor car safely and efficiently. Now we start applying such new methods, taking the whole inspection prior to the installation by analyzing systems' requirements and introducing various system engineering design tools. In this paper, we suggest how to reduce the errors by prelieminarly inspection for the brake facilities using the tools and inspect the needs to analyze the brake facilities' performances.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.144-149
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• 2013

This work deals with the optimal design of a coreless PMLSM (Permanent Magnet Linear Synchronous Motor) with consideration of rising winding temperature. The temperature distribution caused by copper loss in the coreless PMLSM was analyzed using a FEM (Finite Element Method). The thrust and current density where the winding temperature reaches the allowable temperature were calculated. The optimal model provides maximum thrust per unit weight.

• Annals of Clinical Neurophysiology
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• v.7 no.2
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• pp.127-129
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• 2005

We report a 29-year old female who developed bilateral femoral neuropathy combined with multiple abscesses in both thigh muscles. She was present with weakness in both lower extremities for 15 days and intermittent chilling sense for 3 months. Nerve conduction study showed complete absence of compound muscle action potentials in bilateral femoral nerves when stimulated at inguinal area. Electromyographic examination revealed no motor unit action potentials in both rectus femoris and vastus medialis muscles. CT revealed multifocal abscesses in bilateral thigh muscles. After antibiotic treatment, the patient's neurologic symptoms were improved.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.76-82
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• 2009

A worm screw is widely used in a geared motor unit for motion conversion from rotation to linear motion. For mass production of a high quality worm, the current roll forming process is substituted with the milling cutter process. Since the milling cutter process enables the integration of all machining operations of worm manufacturing on a CNC(Computer Numerical Control) lathe, productivity can be remarkably improved. The tooling system for side milling cutter on the CNC lathe to improve machinability is developed. However, the runout of spindle and cutting tips are important factors to be considered for producing high quality worms because the tooling system has multiple tips. In this study, surface roughness variations accuracy according to runout was investigated in side milling cutter for worm screw. The result shows by simulation and experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.773-777
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• 1994

This paper is devoted to the development and performance evaluation of a hard bearing type balancing machine for rigid rotors. The pedestals of the balancing machine are designed to be rigid to be rigid enough to enable the balancing to operate far below the fundamental critical speed. The force measuring method is implemented to the balancing machine. The forces due to unbalance are measured through load cell that are attached to the pedestals. A helical coupling is used for transmitting the driving force from an AC servo motor to the rotor to be balanced. The experimental results show that the current hard bearing type balancing machine can indicate the presence of unbalance beyond 1 .mu. m in specific unbalance unit. The limitation of the current balancing machine is due to the coupling that is likely to make inconsistent offset errors everytime the rotor is connected to the machine.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.29-37
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• 1996

In this study, PC controlled CNC automatic cutting system is developed. Technological introduction of the control process and the computer programming has made possible not only the automatic control for cutting processing unit but also the easy-to-use graphic software that enables the cutting process. This program involves shape part drawing and amendment, pattern reading and saving, reading Autocad file, nesting process, kerf compensation, automatic cutting path generation, NC file conversion and motor control. Software is devided into 3 modules for easy work. First step enables drawing, amendment and pattern making, followed by automatic nesting and cutting path generation with kerf compensation. In the final step, drawing data is transmitted for the resulting automatic cutting processes. This software would be applicated in gas cutting and textile cutting so that it improves the productivity of cutting process.