• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.3
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• pp.171-178
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• 1987

A study of two phase chopper system with four separate groups of DC motors in powering. A novel two phase chopper system with four separate groups of DC motors which applies the principles of two phase chopper with two separate groups of DC motors is dealt with this article. The main circuit consists of eight sets of chopping parts, four diodes and four separate groups of DC motors. Four groups of DC motors are driven through the series and parallel connections to each other in accordance with the operating conditions of the choppers. Although the proposed chopper circuit requires more circuit elements than the conventional two phase chopper system with combined output or two phase chopper system with two separate groups of DC motors, it has the following advantages` (1). It is possible to drive twice as much motors as conventional system does, using esisting receiving-and equipments and motors. (2). It is possible to control load voltage continuously from 0 to source voltage by changing time-ratio from 0 to 1. (3). Load current division becomes equalized. Therefore it is possible to drive not only series motors but also shunt and separately exited motors. (4). When smoothing reactor L is small, harmonic components of the proposed circuit is not so large. Therefore, the value of L can be determined from viewpoints of allowable value of ripple-ratio and current unbalance factor.

• Elastomers and Composites
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• v.40 no.1
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• pp.29-36
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• 2005

Mixing condition and procedure affect properties or a filled rubber compound such as filler dispersion, viscosity, and bound rubber formation. Influence of separate load of styrene-butadiene rubber (SBR) and acrylonitrile-butadiene rubber (NBR) on properties or silica-filled SBR compounds containing NBR was studied. Cure time and cure rate became faster as NBR content increased. The crosslink density increased with increase in the NBR content. The bound rubber content also increased as the NBR content increased. NBR content of the bound rubber was higher than that of the compounded rubber. The bound rubber content was higher when SBR and NBR were loaded separately than when loading simultaneously. The cure time and cure rate were slower for the separate load than for the simultaneous one. The crosslink density was also lower for the former case than for the latter one.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.2
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• pp.148-154
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• 2009

Type A LPG Carrier is the ship using the low temperature independent cargo tank separate from the hull, which has various support structures for laying independent tanks on the hull. In this paper, the direct strength analysis for the support structures has been performed through the direct load analysis, load transfer, stress analysis and strength assessment. Also, a rational modeling method of support structures has been proposed to obtain the dynamic load between the hull and the separate tank.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1076-1078
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• 1998

This paper proposes a new approach for calculating frequency and duration by using the moment matching technique. Two separate expressions are derived, one for the loss of load expectation(LOLE) and the other for the loss of load frequency(LOLF). These expressions are combination of exponentials and are therefore easily integrable and can be readily evaluated. The proposed approach is quite comparable of with the other methods at the aspect of accuracy and efficiency.

• Journal of Power Electronics
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• v.15 no.2
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• pp.327-337
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• 2015

This study discusses the design of a parallel-operated DC-DC single-ended primary-inductor converter (SEPIC) for low-voltage application and current sharing with a constant output voltage. A coupled inductor is used for parallel-connected SEPIC topology. Generally, two separate inductors require different ripple currents, but a coupled inductor has the advantage of using the same ripple current. Furthermore, tightly coupled inductors require only half of the ripple current that separate inductors use. In this proposed work, tightly coupled inductors are used. These produce an output that is more efficient than that from separate inductors. Two SEPICs are also connected in parallel using the coupled inductors with a single common controller. An analog control circuit is designed to generate pulse width modulation (PWM) signals and to fulfill the closed-loop control function. A stable output current-sharing strategy is proposed in this system. An experimental setup is developed for a 18.5 V, 60 W parallel SEPIC (PSEPIC) converter, and the results are verified. Results indicate that the PSEPIC provides good response for the variation of input voltage and sudden change in load.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.3
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• pp.115-123
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• 1985

A two phase chopper system with two separate groups of DC motors for regenerative braking is dealt with in this article. The main circuit consists of two sets of chopping parts, four diodes and two separate groups of DC motors. Although the proposed chopper circuit requires more circuit elements than the conventional two phase chopper system with combined output, it has the following advantages`(1). Ripple frequency of smoothing reactor current becomes twice as high as that of the conventional system, so the continuous current range and the ripple ratio are improved greatly. Therefore, the efficiency becomes even higher, the capacity of commutation equipment is reduced and the inductive interference become less.(2). Load current division becomes equalized. Therefore it is possible to drive not only series motors but also shunt, separately excited and compound motors.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.636-640
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• 2000

A novel integrated battery charger/discharger converter for a standardized battery module is proposed. Instead of using separate charger and discharger converters. it integrates these two converters into a single converter in order to minimize the size. the integrated charger/discharger converter not only regulates the solar array output power including the peak power tracking capability but also controls the battery charging/discharging current depending on the solar array output power and the load power. In addition it offers a regulated bus voltage which simplifies the power distribution/conversion for the pay load.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.41-47
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• 2015

In recent years, energy supply cases to take advantage of EMS(Energy Management System) are increasing according to high interest of energy efficiency. The important factor for essential and economical EMS operation is the supply and demand plan the hourly power demand of building load using the hierarchical clustering method of variety statistical techniques, and use the real historical data of target load. Also the estimated results of study are obtained the reliability through separate tests of validity.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.228-233
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• 2004

A derailment coefficient of railway vehicle is as one of important element that estimate running safety. Derailment coefficient is ratio of lateral load/vertical load happens in contact point between wheel and rail. Lateral load increases, dangerous of derailment can rise. There are ground and vehicle to measurement method of these derailment coefficient. Method of ground is simple, but when vehicles passes data of a point, there is shortcoming that acquire locally. Curved surface style wheel shape that use so far among vehicle method in this research wishes to be not but describe about static load test of wheel-set for derailment coefficient measurement that have plane plate shape that manufacture separate way and correction result etc. to test.

• Smart Structures and Systems
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• v.26 no.6
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• pp.781-796
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• 2020

Prediction of total sediment load is essential in an extensive range of problems such as the design of the dead volume of dams, design of stable channels, sediment transport in the rivers, calculation of bridge piers degradation, prediction of sand and gravel mining effects on river-bed equilibrium, determination of the environmental impacts and dredging necessities. This paper is aimed to investigate and predict the total sediment load of the Wadi Arbaat in Eastern Sudan. The study was estimated the sediment load by separate total sediment load into bedload and Suspended Load (SL), independently. Although the sediment records are not sufficient to construct the discharge-sediment yield relationship and Sediment Rating Curve (SRC), the total sediment loads were predicted based on the discharge and Suspended Sediment Concentration (SSC). The turbidity data NTU in water quality has been used for prediction of the SSC in the estimation of suspended Sediment Yield (SY) transport of Wadi Arbaat. The sediment curves can be used for the estimation of the suspended SYs from the watershed area. The amount of information available for Khor Arbaat case study on sediment is poor data. However, the total sediment load is essential for the optimal control of the sediment transport on Khor Arbaat sediment and the protection of the dams on the upper gate area. The results show that the proposed model is found to be considered adequate to predict the total sediment load.