• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.563-570
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• 2003

When a fault occurs on railway feeders it is very important to detect the fault to protect trains and facilities. Because a DC railway system has low feeder voltage, The fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the load starting current. The load starting current increases step by step but the fault current increases at one time. So the type of $\Delta$I/ relay(50F) was developed using the different characteristics between the load starting current and the fault current. The load starting current increases step by step so the time constant of each step is much smaller than that of the fault current. First, to detect faults in DC railway systems, an algorithm using the time constant calculated by the method of least squares is presented in this paper. If a fault occurs on DC railway systems it is necessary to find a fault location to repair the faulted system as soon as possible. The second aim of the paper is to calculate the accurate fault location using Kirchhoff's voltage law.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.249-251
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• 1994

This paper introduces an implementation of high performance voltage source inverter system based on 16bit micro-processor and DSP for the application to modem rolling stock traction system. In contrast with other industry oriented inverter system, this system requires precise control action complying with various load condition and high overload capability. An asynchronous PWM generation and 3' pulse mode technology are adopted in order to improve compliant starting torque characteristics at starting phase and soft backward-forward starting motion.

• Asia Marketing Journal
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• v.18 no.1
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• pp.23-35
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• 2016

Product customization has been popular since Internet shopping began. Many firms have introduced customization configuration systems, allowing customers to choose a wide range of product attributes, attracting them to participate in the shopping process, and increasing customer satisfaction. Paradoxically, the attribute-by-attribute (AbA) choice in the customization process requires a high-information processing load resulting in shopper confusion. To reduce this confusion, the CvSS (customization via starting solution) system has recently been developed. However, this system provides solution support only for the starting point of the configuration process. Thus, in this study, the authors proposes the CvWS (Customization via Waypoint Solutions) system, which would greatly reduce the customer effort needed to complete the configuration process by using a novel approach to solve the nonlinear knapsack problem. The newly proposed system is theoretically compared with the AbA customization as well as the CvSS system. Also, its feasibility is discussed in the context of the nonlinear multiconstraint knapsack problem.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.148-154
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• 2014

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.65-70
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• 2012

Induction motor is the most widely used to obtain the driving force in the industrial site. Induction motor generates a high current at startup. Most of starting currents are often more than five times of rated current. This high starting current can cause problems such as the voltage drop in the system. In order to solve these problems, if the motor capacity is large, generally we use reactor starting method rather than direct on line starting method. When a high startup current passes through reactor, reactor can serve as a nonlinear elements. In this study, we analyzed that the current, torque and power of the induction motor are different from the change of linear and nonlinear components of the reactor magnetic field.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.1
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• pp.24-28
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• 2014

An induction motor is most widely used to obtain driving force in the industrial field. The induction motor is generated a high current at starting. A starting current is often more than five times of rated current. A high starting current can cause problems such as voltage drop in the power system. In order to solve these problems, a reactor starting method has been widely applied in a large motor capacity. There are differences in the operating characteristics of induction motor corresponding the switching time of reactor tap. In this study, I analyzed that current, torque, power of induction motor are different from changing time and tap setting values of reactor tap.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.7-13
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• 2010

Main starting valve is one of the main parts in the control system of diesel engines, purposed for starting main engines. It is composed of ball valve, check valve, actuator, etc. The design axioms provide a general framework for design methodology. Two axioms are independence axiom and information axiom. These axioms can be applied to all design process in a general way. The first axiom is introduced to analyze and evaluate the design of a main starting valve. The design parameters(DPS) are determined sequentially by considering the independence axiom. For the structural design of a main starting valve, the strength is calculated by using finite element method. In addition, the strength of its actuator piston is evaluated.

• The Transactions of the Korean Institute of Power Electronics
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• v.1 no.1
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• pp.20-26
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• 1996

The common drive method of the single phase induction motor(SPIM) is to install a start capacitor and a centrifugal switch in series with the auxiliary winding. In this paper, the phase angle voltage sequence controller is proposed to eliminate a start capacitor and a centrifugal switch of SPIM. In comparison with the capacitor start system of SPIM, the proposed control system shows that it contributes to saving the starting current about 57% and to improving of the starting efficiency of SPIM. The proposed starting characteristics of the SPIM is obtained with this strategy through simulation and experimental results.

• Journal of Power System Engineering
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• v.10 no.1
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• pp.5-11
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• 2006

During the SI engine starting up, starting conditions directly contribute to the harmful emissions in spark ignition engines. The effects of catalyst temperatures and fuel injection skip methods on HC emissions were investigated. The test was conducted on a 1.5L, 4-cylinder, 16 valve, multipoint-port-fuel-injection gasoline engine. To understand the formation of HC emissions, HC concentration was measured in an exhaust port using a Fast Response Flame Ionization Detector(FRFID). The result showed that HC emissions, which were generated during initial stage of the starting, could be reduced by coolant temperature and fuel injection skips. And through the vehicle test of ECE15+EUDC, it is convinced that the optimized fuel injection skip method according to coolant temperatures have favourable effects on the reduction of harmful exhaust emissions including HC during the SI engine start.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.23-29
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• 2007

The purpose of this study was to examine if there are kinematic variables differences between national representative players (NRP) and non national representative players (NNRP) during 500 m inline skate starting motion. Four NRP and six NNRP were recruited for the study. Each subject executed starting motion five times on a $2{\times}12m$ start way in a gymnasium. Kinematic variables were analyzed by the three-dimensional motion analysis system (60Hz). It was hypothesized that there are difference in elapsed time and center of mass acceleration in starting phase between groups since starting phase has been considered important in sprinting. The results showed that the NRP had significantly shorter starting phase time than that of NNRP. 1) An elapsed time in phase P1 of NRP was shorter than that of NNRP, and excellent players have early started their first stroke. 2) Both NRP and NNRP have started at the same spot, and displacement of the center of gravity in starting posture of NRP group was at the front compared to NNRP group. 3) Average step lengths of NRP were longer than those of NNRP, and a step change of NRP was stabler compared to that of NNRP. 4) In a speed change of the center of gravity NRP showed comparatively high speed from P1 to P4.