• 전기의세계
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• v.28 no.3
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• pp.72-77
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• 1979

The object of this paper is to try to develope Tulular Liner Induction Motor which consists of primary stator that generates traveling magnetic field from the three-phase winding of formed-wound concentric coil, and try to identify the characteristics of starting force. To indentify the theoretical starting force formular we have quoted the conventional Maxwell's basic equation and Poisson's equation which are used in the general machines thereby having obtained the formular of the current with in the conductor and of the air gap magnetic field respectively. General starting force formular is acquired by applying the formular of the current and magnetic field which was theoretically derived above. To this theoretically starting force formula various constants and the values of magnetic flux density resulting from the experimental motor are applied to present theoretically calculated values. Comparing these theoretically caculated values experimentally weighed values, we have proved the validity of theoretical research.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.61-62
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• 2006

Since the starting reactor used for reducing inrush current of high voltage induction motor applies an electric current only when it is at the stage of transition, it gets lots of electrical or mechanical stress. In this aspect, the reliability on the starting reactor is very important because the reactor-relating-accident takes 80% of all the accident concerned with high voltage motor starting panel. In this study, we conducted an insulation test of starting reactor of high voltage induction motor of intake pumping station to the Seoul area And the result from this study was used as data for determining whether it's still usable or not.

• Journal of IKEEE
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• v.22 no.2
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• pp.258-265
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• 2018

This paper proposes an algorithm for reducing the starting current when the single-phase induction motor starts and analyzes its operation. Generally, the single-phase induction motors require several starters to generate the starting torque due to their structural characteristics. In this paper, a capacitor-start / capacitor-run method of the single-phase induction motor is basically adopted. This conventional method is efficient and has a large starting torque, but it generates about 5 ~ 6 times of inrush current at startup. As a result, the freezer starting device and peripheral devices are damaged and life time may be reduced. To reduce the inrush current, the current control algorithm based on the virtual dq model is presented to control the starting current. In addition, it validates the proposed algorithm through experiments to smooth transit from start-up operation to the rated operating region.

• 전기의세계
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• v.22 no.2
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• pp.23-27
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• 1973

An initial starting voltage, ignition time, glow current and blink of the flow starter are changed rapidly in initial using. therefore an ageing is required to stabilize the initial characteristics. According to the experiments, it is proved that the ageing time for the starting voltage and glow current takes 3 minutes and 5 minutes for ignition time and blink.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.925-936
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• 2023

Currently, due to the rapid increase in power demand and the increase in capacity of power converters, the capacity of electromagnetic contactors is also increasing, and the burden on SMPS for the power that can drive them is increasing. Although the initial starting operation current of an electromagnetic contactor is significantly larger than the holding current for maintaining contact, most electromagnetic contactors apply the same voltage as the initial starting operation. An electromagnetic contactor must continuously apply a holding current to maintain the contact point, and the larger the capacity, the larger the current must be applied. This paper proposes a two-level magnetic contactor drive that allows setting the initial starting operation current to fully attach the contact point of the magnetic contactor and the holding current to maintain subsequent operation. In addition, a low-cost drive topology of analog and digital methods was proposed for various field applications, and an algorithm based on the ripple of the excitation current was proposed to determine whether the magnetic contactor was opened or closed without using a separate contact point. The feasibility of the proposed method was proven through Psim simulation experiments.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.1
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• pp.1-6
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• 2016

In this paper, we introduce the characteristics of a vertical PNP transistor that improves start current by decreasing quiescent current with suppressing the parasitic transistor. In order to suppress the parasitic effect, we designed a vertical PNP transistor which suppresses parasitic PNP transistor by using the "DN+ links" without changing the circuit and made a LDO regulator using a standard IC processor. HFE of the fabricated parasitic PNP transistor decreased from conventional 18 to 0.9. Starting current of the LDO regulator made of the vertical PNP transistor using the improved "DN+ linked" structure is reduced from the conventional starting current of 90mA to 32mA. As the result, we developed a LDO regulator which consumes lower power in the standby state.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.206-212
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• 2017

Induction motor torque is the reactive power is needed which corresponds to the exciting current to generate the magnetic flux as the product of current and flux. For use in the method of supplying the required reactive power to the induction motor power factor correction apparatus using a lot of ways to supply in place of the power supply side, when using a power factor compensation device can reduce the apparent power, the power factor can be improved. However, the distance to the emergency generator transformers or motors from the motor capacity is smaller but short and difficult to maneuver the theory and practice of the operating characteristics of the starting characteristics of the motor used a lot of large industrial plants were measured and analyzed. Therefore, this study investigated the motor starting Analysis and interpretation for the relationship with the large motor starting torque and speed during motor starting.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1090-1100
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• 2017

This paper presents the comparison of starting current characteristics of a three-phase induction motor fed by two types of soft starters. The first soft starter under investigation is a conventional AC voltage controller on the basis of a phase-control technique. The other is the proposed asynchronous PWM AC chopper which is developed from the conventional synchronous PWM AC chopper. In this paper, the proposed asynchronous PWM AC chopper control scheme is developed by generating only two asynchronous PWM signals for a three-phase main power circuit (6 switching devices) from a single voltage control signal which is compared with a single sawtooth carrier signal. By this approach, the PWM signals are independent and easy to implement since the PWM signals do not need to be synchronized with a three-phase voltage source. Details of both soft starters are discussed. The experimental and simulation results of the starting currents are shown. It is found that the asynchronous PWM AC chopper efficiently works as a suitable soft starter for the three-phase induction motor due to that the starting currents are reduced and are sinusoidal with less harmonic contents, when being compared with the starting current waveforms using the conventional phase-control starting technique. Also the proposed soft starter offers low starting electromagnetic torque pulsation.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.700-706
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• 2012

The core technology of a starting device in the packaged power system is the pinion gear shifting device and to limit the initial starting voltage. Although the conventional products have been used the starting controller using mechanical contactor, these have a big problem such as the uncertainty for the start of starting motor after a pinion gear is completely shifted or the arc demage due to high current. In this study, in order to solve these problems, we designed and fabricated a new product to achieve the safety and reliability as follows: the pinion gear-shifting control circuits to eliminate the uncertainty of the start, the starting control system using semiconductor device to prevent the arc demage of contactor caused by high current, a start safety devices for soft starting of series motor. In addition, we obtained the electrical safety by separating the pinion gear control circuit and the source circuit of motor.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.807-808
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• 2006

This paper covers start-up characteristic of three phase induction motor. When three phase induction motor is started, the inrush current occurs. There are several ways of reducing starting current of a three phase motor. In this paper will explain and propose the types of part windings in order to reduce the starting current.