• Title, Summary, Keyword: Axial field

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Design and Characteristic Analysis of Double Stator Axial Field 12/10 SRM (이중고정자 횡축 12/10 SRM의 설계 및 특성 해석)

  • Son, Dong-Ho;Ahn, Jin-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.6
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    • pp.730-737
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    • 2018
  • This paper aims to design of a double stator axial field 12/10 SRM. Conventional and single stator axial field SRMs were reviewed to apply for automotive cooling fan. The axial field SRM has the advantage of shorter flux path, higher torque per volume and lower iron loss. However, there is axial eccentricity in single stator axial field SRM due to one side excitation. Therefore, a double stator type is designed in this paper to reduce the axial eccentricity. And the trapezoidal pole shape of the stator increases the flow of magnetic flux from stator to rotor and the torque region. The torque and efficiency are compared and tested with experiments.

Interaction of Magnetic Flux Ropes in Relation to Solar Eruption

  • Yi, Sibaek;Choe, G.S.
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.45.2-45.2
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    • 2018
  • Twisted magnetic flux tubes (also called magnetic flux ropes) are believed to play a crucial role in solar eruptive phenomena. The evolution of a single flux rope with or without the influence of an overlying field of a simple geometry has been extensively studied and its physics is rather well understood. Observations show that interacting flux tubes are often involved in solar eruptions. It was Lau and Finn (1996) who intensively studied the interaction between two flux ropes, whose footpoints are anchored in two parallel planes. In this too simplified setting, the curvature of the flux rope axial fields is totally ignored. In our study, the footpoints of flux ropes are placed in a single plane containing a polarity inversion line as in the real solar active region. Our simulation study is performed for four cases: (1) co-axial field and co-axial current (co-helicity), (2) counter-axial field and co-axial current (counter-helicity), (3) co-axial field and counter-axial current (counter-helicity), and (4) counter-axial field and counter-axial current (co-helicity). Except case 3, each case is found to be related with certain eruptive features.

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The Magnetic Field Characteristics of Multipolar Axial Magnetic Field type Electrodes for Vacuum Interrupter (진공인터럽터용 다극 종자계전극의 자계분포 특성)

  • Kim, Sung-Il;Park, Hong-Tae;Ahn, Hee-Il
    • Proceedings of the KIEE Conference
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    • pp.92-94
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    • 1999
  • This paper describes axial magnetic field characteristics of multipolar axial magnetic field type electrodes for vacuum interrupter used in vacuum circuit breaker. It was distinguished that axial magnetic field distribution in consideration of eddy current effect between electrodes by finite element method. Throughout experiment of magnetic field measurement, confirmed validity of numericla analysis.

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A Study of the Characteristics on the Vacuum Interrupter with Axial Magnetic Field Type using 3 Dimension Finite Element Analysis (3차원 유한요소해석을 이용한 종자게형 진공 인터럽터의 특성고찰)

  • 하덕용;강형부
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.5
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    • pp.460-467
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    • 2002
  • This paper deals with the distribution characteristics of the current density and axial magnetic flux density on the vacuum interrupter with axial magnetic field type using 3 dimension finite element analysis. An axial magnetic field parallel to the current flow in the arc column can improve the current breaking capacity of vacuum interrupter by affecting the arc mode. The axial magnetic flux density on the contact electrode surface is analyzed by inputting external current as a function of the transient time for sine half wave. And it also is analyzed within the gap distance of the contact electrode. The peak value of current but is decreased with the descending current on the contact electrode surface and within the gap distance of the contact electrode. The residual magnetic field is generated on the contact electrode surface and within the gap distance in the instant of zero current, which is due to the influence of eddy currents. The phase shift due to eddy currents, defined as time difference between the maximum value of current and axial magnetic field, is about 1ms in the center point of gap distance.

Aberration Correction of an Off-axial-field Two-mirror System Using a Decentered Aperture (비축시야 2반사광학계에서 조리개의 편심을 이용한 수차보정)

  • Lee, Jong-Ung
    • Korean Journal of Optics and Photonics
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    • v.31 no.1
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    • pp.20-25
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    • 2020
  • To design a wide-field two-mirror system, the system must feature an off-axial field, to avoid ray obstruction and field screening by the secondary mirror. The off-axial aberrations of the system cannot be corrected sufficiently, though, because there are only a few design parameters. The present study designs an improved off-axial-field two-mirror system using a decentered aperture stop.

A Study on the Development of Vacuum Interrupter with Axial Magnetic Field type (종자계방식 진공인터럽터 개발에 관한 연구)

  • Kim, Sung-Il;Park, Hong-Tae;Ahn, Hee-Il;Seo, Jung-Min
    • Proceedings of the KIEE Conference
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    • pp.943-945
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    • 2000
  • In this paper described that study on the distribution and characteristics of axial magnetic field by mathematical analysis and experiment for axial magnetic field type vacuum interrupter that important part on vacuum circuit breaker. And, it was shown that inspected results of arc shape at breaking the current by typical axial magnetic field type model and new axial magnetic field type model.

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Influence of the length and width of the slots of contact electrode on axial magnetic field at the mid-gap in 4 segment coil type vacuum interrupter (4 segment 코일타입 전극구조의 진공 인터럽터에서 접점전극의 슬롯의 길이와 폭이 전극사이의 측자계에 미치는 영향)

  • Kim, Byong-Chul;Yoon, Jae-Hun;Park, Seong-Hee;Kang, Seong-Hwa;Lim, Kee-Jo
    • Proceedings of the KIEE Conference
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    • pp.210-211
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    • 2007
  • Once high current flows through the vacuum interrupter, eddy current occurs due to the time-varying axial magnetic field caused by the current(AC) and it causes a decrease in axial magnetic field generated by current flowing through coil electrode. but if there are slots on contact electrode it is possible to increase the amplitude of axial magnetic field by reducing the influence of eddy current. there has been many studies about the number of slot of the contact electrode[1][2][3]. In this paper, in addition to these previous results we deal with the influence of the length and width of the slots on axial magnetic field at the mid-gap plane in 4 segment coil type vacuum interrupter by using 3D finite element method software.

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Evolution of Coronal Magnetic Fields Consisting of Flux Ropes and Overlying Fields

  • Jun, Hongdal;Yi, Sibaek;Choe, G.S.
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.69.1-69.1
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    • 2019
  • A series of numerical MHD simulations are performed to investigate the evolution of coronal magnetic fields consisting of two flux ropes and an overlying field. Depending on the directions of the axial current and the axial field, two co-helicity cases and two counter-helicity cases are addressed. In Case 1, in which both the axial currents and the axial fields are parallel, flux rope merging bears a huge flux rope with a large winding number. This flux rope naturally erupts, but the whole evolutionary process is rather slow. In Case 2, in which the axial currents are parallel while the axial fields are antiparallel, a self-closed structure is formed and it drives eruption. In Case 3, in which the axial currents are antiparallel and the axial fields are parallel, each flux rope erupts independently and the presence of the other flux rope does not affect the eruption of one flux rope. In Case 4, in which both the axial currents and the axial fields are antiparallel, interaction of the flux ropes and the overlying field effects a breakout reconnection creating an apple-like CME configuration. Our study tells what kind of eruption mechanisms are involved for different eruption features observed.

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The Development of Axial Magnetic Field Type Vacuum Interrupter (종자계형 진공인터럽터의 개발)

  • 박홍태;안희일;김성일;이경행
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.231-233
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    • 2001
  • Axial magnetic field(AMF) type electrodes can be increase the interrupting capability of vacuum interrupters. Depending on the design, the principle of the local axial magnetic field arrangement are different. In this paper, a new AMF contact design based on a unipolar field arrangement and its characteristics are introduced. The influence of the unipolar AMF on the arc behavior is described by high-speed video camera. In addition, three-dimensional AMF simulations have been peformed by means of a finite element analysis(FEM) program to analyze the influence of magnetic field distribution on the AMF performance. The high interrupting capability of the unipolar AMF type electrode has been confirmed by three-phase test.

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A Study on the Effect of the Contact Electrode Slits in the Vacuum Interrupter with Axial Magnetic Field Type (종자계형 진공 인터럽터에서 접점전극 슬릿의 영향에 관한 연구)

  • 하덕용;강형부;최승길;최경호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.9
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    • pp.822-829
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    • 2002
  • This paper deals with the distribution characteristics of the current density and axial magnetic flux density for each slits made on the contact electrode in the vacuum interrupter with axial magnetic field type using 3-dimension finite element analysis. It has been known that the presence of an axial magnetic field parallel to the current flow in the arc plasma can increase the high current breaking capacity of vacuum interrupter by carrying out the arc plasma from constricted mode to diffusion mode. The axial magnetic field is created of itself by current flow in the segments of coil electrode behind the contact electrode. The analyzed results show that if the slits are made in the contact electrode, they can increase the current density and axial magnetic flux density in the contact electrode surface and at the gap distance, which is due to decrease the effect of eddy currents flowing in the contact electrode. The phase shift due to eddy currents, defined 3s time difference between the maximum value of current and axial magnetic field, is decreased still more by increasing the number of slits made in the contact electrode at the center point of gap distance. These results demonstrate that 3-dimension finite element analysis has a great deal of merits in the development and evaluation of new electrode at the design of vacuum interrupter.