• Journal of the Society of Naval Architects of Korea
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• v.50 no.6
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• pp.407-413
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• 2013

In the conventional towing tank, the ordinary towing carriage has a speed barrier which caused not only by the limitation of the length of towing tank but also the limitation of acceleration. Therefore the length of the towing tank should be decided carefully from the planning stage of the towing tank construction. Consequently the acceleration of the towing carriage should be taken less than 0.06g practically to avoid the slip of the wheel on rail. Due to the increasing demand of the high speed experiments on the development of special novel ship, the requirement of the high speed towing carriage is continuously increased recently. When the minimum measuring time of the towing experiment is prescribed as five seconds, the carriage should be accelerated with higher than 0.12 g to get the speed of 18 m/sec even in the towing tank having a length of 400m in length approximately. This means that the requirement of acceleration is bigger than twice of the ordinary practices of carriage acceleration. In such a condition the exerted total power of motor could not converted to traction force for the acceleration of the carriage without slip. To over come these difficulties a pair of horizontal traction wheels are reinforced to each of the ordinary vertical carrier wheel and appropriate suspension system has been devised for the towing tank of super high speed operation. It is believed that the design of novel suspension system adaptable for the high speed acceleration of towing carriage will play a important role as a reference for the remodeling of the towing tank for high speed experiment.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.129-136
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• 2005

This paper presents a design strategy of SPOKE type BLDC motors considering an irreversible demagnetization of a permanent magnet (PM). So the irreversible demagnetization characteristic of the motor is analyzed by rotor structure. The instantaneous currents in either starting or lock rotor condition, which are calculated from the current dynamic analysis, are applied to the analysis of the irreversible demagnetization field by FEM. In irreversible demagnetization analysis by FEM, the variation of residual flux density in PM is analyzed using the non-linearity of magnetic core on B-H plan. The analysis results are compared to several rotor structures and used for optimize the rotor structure.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.250-252
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• 2008

DC traction system generates leakage current because running rails are used in return circuit. And it is very important to estimate the leakage current to the train operation situation. Therefore this paper presents dynamic simulation technique that is very similar to the real operation situation using TPS and PSCAD/EMTDC. For this we model DC traction system included in DC substation, variable feeding circuit model and variable train model. And we extract train location and power using TPS program and use these data for dynamic simulation. Finally we can estimate leakage current to the various operation condition using dynamic simulation.

• Tribology and Lubricants
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• v.21 no.6
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• pp.272-277
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• 2005

Continuously variable transmission (CVT) of toroidal type has a elliptical shape of contact zone under the elastohydrodynamic lubrication (EHL) condition, where the power is transmitted only by shearing the lubricant. Due to the small contact area of elliptical shape, the traction of the shear behaviors of lubricant over the contact zone is under extremely high contact pressure over 1.0GPa. During the power transmission by shearing the fluid, many kinds of mechanical movements occur such as squeezing, sliding, rolling and spin. Among the movements, the spin effect that is the most undesirable contact behavior in transmitting the power frequently makes significant abnormal wear damage. In this work, the analysis of elliptical contact of EHL with spin effect is performed, which will give very useful information to understand the traction behaviors in toroidal type of CVT system.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1430-1432
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• 2001

In this paper, 200-class insulation system for form-wound stator coils is designed for form-wound stator coils is designed for AC traction driven with VVVF inverter. Model coils are made to embody all essential elements representing a winding insulation system and structure. Acceleration degradation for model coils is applied exposure to heat(235$^{\circ}C$). In order to investigate the condition of the coils and to determine their insulation reliability, high voltage test and the dielectric properties such as dielectric loss and capacitance are performed. Also, partial discharge measurement is investigated for internal defects.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.271-281
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• 2000

A number of variables and environment are concerned for the basic design of train. The design of train ran be optimized by the ruining simulation. And using the simulation result the consuming energy, regenerating power, adhesion coefficient, train traction control capacity are respectable. Considering these variables and for more information operating time, operating period, standard velocity and limit speed, the all factors of train are optimized. The light-tail tram is mainly divided into linear motor train, road surface train, iron wheel train and rubber tire train, and the most profitable one for adhesion coefficient is rubber tire train and the train will be designed.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.843-851
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• 2007

It is known that bogie frame must have sufficient stiffness for car body and passenger weight and transfer traction and braking force, and as of today most studies and verifications are restricted to static and fatigue analysis for force acted on bogie frame. Bogie frame is mounted with equipments to control the signal, traction and so on, this equipment's behavior is subjected to vibration mode occurs on running condition. If the resonance occurs on this equipment, the possibility of crack occurrence on bracket connected with equipment and bogie frame will be increased. In this paper, the method of vibration strength verification for bracket attached on bogie frame will be introduced by using frequency response method.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.348-354
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• 2003

An analysis of the dynamic behavior between disk and roller has been performed when the torque is transmitted to toroidal IVT (Infinitely Variable Transmission). The contact area, shape and pressure with elliptical shapes between disk and roller are computed as the transmission ratios are changed. This study will give the information of contact shapes between roller-input dist and roller-output disk which are working under the most severe condition. The computed results are expected to guide the design criteria for the enhanced endurance li(e. Furthermore, the investigation of contact behaviors is very crucial to develop the traction oil that the efficiency of IVT system is most dependent on.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.310-315
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• 2001

The most general feature of contact zone among the mechanical components is elliptical circle. In particular, continuously variable transmission (CVT) of toroidal type has elliptical shape of contact zone under the elastohydrodynamic lubrication condition, where the power is transmitted by the shearing the efluid. Due to the traction of the shear behaviors of lubricant over the small elliptical contact zone, high power of torque is transmitted. During the power transmission, many kinds of mechanical movements occur such as squeezing, sliding, rolling and spinning. The spinning effect that is not common contact behavior in tribological components frequently makes significant abnormal wear damage. In this work, the analysis of elliptical contact of elastohydrodynamic lubrication with spin effect is performed, which will give very useful information to understand the traction behaviors in toroidal type of CVT system.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1188-1194
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• 2008

To cope with the demagnetization risk of permanent magnets used in Interior Permanent Magnet Synchronous Motors(IPMSM), an accurate iron analysis and thermal analysis are very important. In this research, to calculate thermal increment of IPMSM for high-speed traction motor, we will extract losses of IPMSM considering the condition of field weakening control. Then we will input the calculated losses such as iron loss and copper loss as the thermal sources. Based on magnetic filed and thermal analysis, we will support the design of IPMSM for high-speed train.