• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.705-713
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• 2012

In this paper, a novel 12/14 hybrid pole type bearingless switched reluctance motor (BLSRM) with short flux path and no flux-reversal in the stator is proposed. The proposed BLSRM has separated rotating torque and suspending force poles. Because of independent characteristics between torque and suspending force poles, the torque control can be decoupled from the suspending force control. Due to the short flux path without any reversal flux, compared to the 8/10 hybrid stator pole BLSRM, the output torque is significantly improved and the air-gap is easier to control. Meanwhile, basic design principle for the proposed structure is described. To verify the proposed structure, finite element method (FEM) is employed to get characteristics of the proposed structure and 8/10 hybrid stator pole BLSRM. Based on the analysis, a prototype of the proposed BLSRM is designed and manufactured. Finally, validity of the proposed structure is verified by the experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.123-125
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• 2001

Salient pole rotor type single phase SRM(switched reluctance motor) uses the magnetic fluxes of radial and axial direction at the same time. Therefore the output power per unit volumn is very high and shaft length can be shorter than any other types of SRM with same output. Also, It can be manufactured with low cost thanks to simple structure and driving circuit. We already designed and manufactured prototype using the dynamic output equation of general rotating machine but the effect by salient pole structure was not considered. The most optimal design parameters for salient pole rotor type single phase SRM will be selected by comparing and analyzing the results from 3D FEM analysis, experimental values of the torque versus speed characteristics. and the nux linkage of prototype. Results for the former 3D FEM analysis and torque vs. speed characteristics were already obtained. Finally, we will measure the nux linkage of salient pole rotor type single phase SRM.

• 전기학회논문지
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• 제56권5호
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• pp.860-868
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• 2007

In this paper. design of spoke type BLDC motor which have a characteristics of concentrating fluxes and relatively high reluctance torque among IPM BLDC motors has been researched. To reduce cogging torque and torque ripple. rotor pole shape of optimal design is proposed. To clearly see the effects due to the changed rotor pole shape. magnetic circuit model. 2D FEM and design of experiments (DOE) are used. Then considering these results proper rotor pole shape which have an good effect on air gap flux density and cogging torque. back-emf is designed. Moreover. the validity of proposed model in this paper is also verified by comparison between gained experiment and analysis data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.482-487
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• 2001

This paper introduces a Lorentz force type four-pole self-bearing motor, where the new pole arrangement of a stator is intended to function both as a synchronous PM motor and as a magnetic bearing. The Lorentz force type has some good points such as linearity of control force, freedom from flux saturation, and high efficiency unlike conventional self-bearing motors. Mathematical expressions of torque and radial force are derived to show that they can be separately controlled regardless of rotational speed and time. To verify the proposed theory, a prototype is made, where a ring-shape outer is actively controlled in two radial directions while the other motions are passively stable supposing the radial stability. Through some experiments, it is shown that the proposed scheme can provide high capability and feasibility for a small high-speed self-bearing motor.

• 전기학회논문지
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• 제67권6호
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• pp.702-707
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• 2018

In case of Lighting occurs in Domestic combined distribution line, normally the voltage for the neutral line increase dramatically. General connection for underground cable is bundled common earth type so the lightning over voltage increase at the concentric-neutral line is not big enough to give impact on cable sheath. But in case of Non bundled common earth type it is necessary to analyze the phenomena on cable sheath caused by lightening overvoltage. Especially pole and cable joint are the core factor to consider. In this paper concrete pole and cable joint were evaluated in case of Non bundled common earth type combined distribution Line. EMTP simulation model has been designed and several case study were made. Also several experimental test were made to verify the simulation result.

• Journal of Welding and Joining
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• 제19권6호
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• pp.622-629
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• 2001

The aim of this experiment is to establish the method that obtains symmetrically two nuggets in microresistance series spot welding. The sheets of austenite stainless steel STS304 applied to various electronic parts were experimented by the inverter welding power source of polarity controllable type and by the twin head for left and right electrode force to be controlled separately. The experimental results were obtained as follows : 1) When series spot welding was carried out by DC 1 pulse as welding current with same electrode force at left and right, the asymmetry of nuggets was resulted from the larger nugget of the (-) pole because of the Peltier effect. The dynamic resistance of weld spot at left and right was appeared differently according to the growth of nuggets. 2) When AC 1 cycle by welding power source of polarity controllable type was applied, the nuggets were almost symmetrically formed. 3) In a twin head, if the electrode force of (-) pole was larger than that of (+) pole, the diameters of two nuggets became to same. It was confirmed that the dynamic resistance of (-) pole was decreased to the same level as it of (+) pole. 4) Although the forces of left and right electrode were same, and only DC 1 pulse was applied, symmetric nuggets were obtained if the conductivity of (+) pole was lower than it of (-) pole.

• ETRI Journal
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• 제19권2호
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• pp.48-58
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• 1997

Using high quality high-$T_c$ superconducting (HTS) YBCO thin films, we designed and fabricated 3-pole, 5-pole, and 7-pole lowpass filters consisting of microstrip transmission lines and open-stub lines. We measured the microwave response of the filters in the temperature range of T=85 K to 27 K. AtT=30 K, the observed inband insertion loss was 0.14dB and 0.02dB for the 5-pole and 7-pole filters, respectively. The cut-off frequency was 4.7 GHz for the 5-pole filter and 7.9GHz for the 7-pole filter. To the authors' knowledge, the measured inband insertion losses are the best values reported so far for the open-stub line type HTS multipole lowpass filters. The skirt property of the 5-pole filter showed a large improvement over that of the 3-pole filter as predicted from the simulation. We found that, to obtain a stable performance, the HTS multipole lowpass filters should be operated at the temperatures between 60% and 70% of $T_c$.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.211-215
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• 2006

This paper presents a new structure for the universal motor using soft magnetic composite (SMC). The stator for this new type of motor is made by combination of the SMC pole and the silicon steel yoke. The shape of the 3D SMC pole is designed to minimize ohmic loss and amount of stator coil. To design the pole shape, the 3D analysis in the design procedure is replaced with an equivalent 2D analysis. Finally, the optimal shape is analyzed by 3D FEM and the performance is discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.655-659
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• 2006

This paper presents a novel electrostatic drop-on-demand inkjet device featured by a MEMS fabricated pole-type and hole-type nozzle with tube shaped orifice and investigates the feasibility of applying the inkjet device to display fabrication process. The electric voltage signal applied to the ring shaped upper electrode plate, against the hole-shaped ground or pole-shaped ground, referred here pole-type and hole-type nozzle respectively, allows ejection of small droplet to take place: That is, a tiny droplet is taken away from the peak of the mountain shaped liquid meniscus formed at the nozzle orifice. It is verified experimentally that the use of the pole type nozzle allows a stable and sustainable micro-dripping mode of droplet ejection for a wider range of applied voltages and of liquid viscosities. This demonstrates a feasibility of electrostatic drop-on-demand inkjet device as a disruptive alternative to conventional print heads such as thermal bubble or piezoelectric inkjet heads.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제9권1호
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• pp.63-72
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• 2002

An inverse interpolation problem for rational matrix functions with a certain type of symmetricity in zero-pole structure is studied.