• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1420-1423
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• 1990

DC series motor has been widely applicated in industry due to many advantageous characteristics, such as high starting torque, easy construction of its controller, and cost economy, etc.. However, by high starting current, excessive surge voltage, and so on, many problems which could make engineers relinguish to use it are induced. In this paper, various protection methods for power circuit are discussed. Particularly, a new proposed snubber circuit which consists of two diodes, one capacitor, and a resistor increases the performance with respect to the suppression of the surge voltage. Furthermore, the plugging algorithm, by checking the armature current and voltage and controlling the field coil current, is designed and implemented. Also, these methods and algorithms were applicated in electric vehicle, and we could find its stability to be considerably improved.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2268-2275
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• 2018

This paper presents a high-efficiency low-power permanent magnet (PM) generator for the power supply of the generator exciter. In the conventional generator system, the power for the exciter is fed by the generator output power or an emergency battery for the starting. The proposed low-power PM generator can generate the proper power and voltage to excite the exciter field winding. According to the starting of the generator, the designed PM generator can supply the constant voltage to the Automatic Voltage Regulator (AVR), then it can be used to control of exciter field current for the generator. Because of the designed PM generator which is placed inside the conventional generator system, the emergency battery and Potential Transducer(PT) for AVR can be removed. Thus, the total efficiency can be improved. The proposed generator system is tested in the practical system. And the efficiency characteristic is analyzed.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.849-851
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• 2001

This paper presents experimental method of parameter measurement and starting characteristics of 3 phase induction motor. Equivalent circuit parameters measured by DC test, the blocked rotor test, and no load test were used as the input data for computer simulation. Starting characteristics, such as starting current and torque were analyzed through computer simulation by Matlab, and the simulation results were compared with experiment using strain gauge attached on motor shaft. We conform that experimental results are very similar to that of simulation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.1
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• pp.70-76
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• 2000

This paper describes a one-chip micom controller and phase angle control method for self-starting and energy saving of single-phase induction motor. The proposed method is based on the optimal efficiency control which is running by variable phase angle of main winding current such as to maintain the maximum efficiency characteristics of the motor, in voltage control with TRIAC. Experiments are focused on a capacitor starting single-phase induction motor. The optimal energy saving by variable phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

• 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.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.974-976
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• 1993

A design method of three phase induction motors that have characteristics of low starting current and high starting torque is proposed. This design method is based on the traditional theory related to the skin effect and the gap saturation effect. The starting performances and the analysis method are explained in short. Finally, comparison of example design data on electric hoist motor with standard motor is shown.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.3
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• pp.148-151
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• 2004

For turn on high pressure sodium vapor lamp, Starting Voltage is very important factor. This starting voltage supply to high pressure sodium vapor lamp as electric discharge lamp, Electric field is producted in electric discharge tube, So accelerative electron collide against vapor atom and second electron is generated, And rapidly the current flow to electric discharge tube. This starting voltage is high voltage and source for melting contact that relay is according as turn on/off high pressure sodium vapor lamp. Consequently, This paper propose that the prevention of melting contact in accordance relay of controller for turn on/off high pressure sodium vapor lamp.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1279-1281
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• 2005

Generally a single-phase SRM(switched reluctance motor) has several stator and rotor poles but these are excited by one regulated current at the same time. It has only one inductance variation. It means that the positive torque is only generated in the positive slope of the inductance variation. The single-phase SRM can not be started by itself. The single-phase SRM can be started by itself if the rotor is placed in the positive slope of the inductance variation. Then, the starting device is required to place the rotor in the starting position before start. On this paper, the equation of the force requisite for the starting device is derived using by the frictional force of the rotor

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.350-352
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• 1995

The starting characteristics of single phase induction motor(SPIM) is described by control of phase and voltage. Auxiliary winding voltage is controlled by DC amplifier and phase is integrator. These processes enable comparison of torque with slip in each voltage and phase angle variations. Simulation and experimentation results of the motor's torque-slip characteristics using the controlled auxiliary winding voltage and phase angle arc shown and discussed. As a results, starting time is fast and main winding current is small when auxiliary winding voltage is low than rating voltage and starting characteristics is good in phase angle $90^{\circ}$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.12
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• pp.55-60
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• 2015

PG and RG methods are widely known method for calculating the capacity of the emergency generator in construction electrical installation. PG and RG methods are mainly used as a saving a life, fire protection, fire fighting in construction. Because no long distance between the emergency generator and electric motor feeder, the relatively small motor power in construction electrical installation, the capacity of generator in PG and RG methods are little problem of voltage and reactive power of generator. However in many cases the application of the PG and RG method is difficult in the Chemical Plant because it is long distance between the generator and the motor Feeder and motor capacity is very large. Motor starting power factor is about 0.2 lagging power factor and motor starting current is about 6times during motor staring. Also Most of the staring current component is a reactive power component. therefore, it is many cases that lack of reactive power and excess of allowable voltage drop limit and After selection of emergency diesel generator, problems happen during motor starting. Therefore, to be selection of effective emergency generator, active generator power, reactive power and the required reactive power during large motor starting should be considered in chemical plant. It is also required of the verification process through simulation because hand calculation is very difficult considering study cases.