• Journal of Magnetics
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• v.18 no.2
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• pp.207-211
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• 2013

In a coaxial magnetic gear, bridges connecting separate pole pieces are useful for fabrication and also improve mechanical reliability. However, they have a negative influence on electromagnetic performance parameters such as transmission torque and iron loss. This paper investigates the effect of stationary pole pieces connected by bridges on the electromechanical characteristics. The bridge type and thickness are the main parameters influencing the performance of a coaxial magnetic gear. The inner, center, and outer bridge types each show the best performance in terms of different characteristics. However, for any bridge type, an increase in the bridge thickness reduces the overall electromagnetic performance, except for the torque ripple, and improves the overall mechanical performance, including the deformation, von Mises stress, and natural frequency of the stationary part.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.7
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• pp.473-482
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• 2004

In this paper, a detection technique of initial rotor position at a standstill in Toroidal Switched Reluctance Motor(TSRM) with built-in interior central pole search coil is proposed. In case search coils are used as a position sensor, it has many advantages like low cost, decrease in the volume, high robust characteristics and wide applications. However, the initial rotor position detection is very difficult because the search coil's EMF is not exist at a standstill. In this paper, a new detection method of initial rotor position is suggested using interior central pole search coil. The simulation and experiment for the proposed method and their results support the validity of the proposed scheme by verifying the operation of a 6/4 TSRM using search coils.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.1
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• pp.99-105
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• 1997

In the paper, aging of insulating oil in pole transformer has been studied by performing accelerated thermal aging test. Dissolved gases were extracted by air bubbling method. Concentration of dissolved gases were modified by extraction ratio of each gases in insulating oil. Aging of insulating materials were proceeded by thermal degradation and oxidation reaction. Both of the reactions followed zeroch order kinetics. Formation rate equations for hydrocarbons, carbon oxides, and hydrogen were derived. It was conformed by gas analysis and UV-Visible spectrophotometric method that iron core and copper coil in pole transformer act as catalyst during the aging process.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.3
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• pp.247-255
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• 1989

This paper proposes an error model with integral action and a pole-place-ment self-tuning controller for robot manipulators in task coordinates. The controller can reject the offset due to any load disturbance without a detailed description of the robot dynamics. The error model parameters are estimated by the recursive least square identification algorithms, and controller parameters are determined by the pole-placement method. A computer simulation study has been conducted to demonstrate the performance of the proposed control system in task coordinates for a 3-joint and 2-link spatial robot manipulator with payload.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.535-542
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• 1996

A zero voltage switching (ZVS) three level auxiliary resonant commutated pole inverter (ARCPI) is presented for high power GTO inverters. The concept of ARCP for two level inverter is extended to the three inverter. The proposed auxiliary commutation circuit consists of one resonant inductor and two bi-directional switches, which provides ZVS condition to the main devices without increasing device voltage or current stresses. The auxiliary device operates with zero current switching (ZCS) which enables use of the low cost thyristors. The proposed ARCPI can handle higher voltage and higher power (1-10MVA) comparing to the two level one. Operation and analysis of the ARCPI are illustrated and the features are compared o those of the snubber circuit incorporated three level inverter. Experimental results with 10kW, 4kHz prototype are presented to verify the principle of operation. (author). refs., figs., tab.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.583-591
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• 2000

It this paper the multilayer chip band pass filter for next generation mobile communication phone is fabricated and designed. For the design the multilayer chip filter of non-contented equivalent circuit and contented equivalent circuit with attenuation pole is presented. Finally it is fabricated and designed using the multilayer chip filter of contented equivalent circuit with attenuation pole. The size insertion loss center frequency and band width of multilayer chip filter are 4.5$\times$3.2$\times$2.0[mm], 3.0[d.B] and 1945$\pm$25 MHz respectively. The multilayer chip filter was fabricated by screen printing with Ag electrode after tape casting. Simulation results of multilayer chip filter are compared with experimental results and found to be in excellent agreements.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.59-64
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• 2006

In this paper, developed a uninterruptible hotline tools and method for replacement of strain pole crossarm on overhead distribution line. For practical use of developed tools, following direct hot-line methods were proposed: 'Direct hot-line method for replacement of pin pole crossarm', 'Direct hot-line method for alteration of crossarm' and 'Crossarm replacement method in uninterruptible cable displacement area'. These methods were proposed more simple and safe working on hotline job.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.426-431
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• 2006

The case where a drain cannot flow backwards, a sewer institution can be unmanageable in this, and a mad is under water momentarily by local heavy nin by the climate phenomenon in spite of not being a lowlands belt has occurred well more than recently. By the flooded mea since it is in the state which has some human bodies at hand, when a short circuit occurs in street lighting pole which is the electric institution thing of a road, the danger of an electric shock accident becomes higher. In this paper, it was going to show improvement plan for grasping the brittle factor of street lighting pole electricity facilities through the on-site survey of street lighting pole electricity facilities, and improving this.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.5
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• pp.67-72
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• 2011

In this study we investigate the background of UPS output transformer(${\Delta}-Y$) operation on neutral ungrounded system, and perform field experiment of neutral floating-phenomenon for the inter-locked securing of electric facilities and improvement of neutral floating-phenomenon. Experiment results show that a floating-phenomenon occurs when four-pole input-breaker trip and the neutral to earth voltage occurring concurrently is identified as phantom voltage. And the measures for the transient overvoltage that can occur in floating-state also are investigated. As a result, the risk elements of neutral ungrounded method as well as neutral floating-phenomenon are removed by installation of separate solidly-grounded transformer and switching four-pole input-breaker to three-pole input breaker.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.108-113
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• 2013

Change of supply voltage, customer load, output of distributed generation, etc cause voltage change in distribution system. OLTC and SVR are usually used to supply normal voltage at customer. But usage of these devices is inefficient and uneconomical in certain circumstances. To solve this problem, new pole transformer which has automatic tap changer is developed. The transformer changes tap when voltage changes. And it has latch switch and reactor for supplying power without outage. To verify normal operation of tap changer, test is conducted. SVR and 50kVA load is used for test.