• Title, Summary, Keyword: magnet ring

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Characteristic analysis of permanent magnet synchronous motor with full-ring magnet (Full-Ring 영구자석을 갖는 영구자석 동기 전동기의 특성 해석)

  • Jang, Seok-Myeong;Park, Ji-Hoon;Choi, Jang-Young;Kim, Il-Jung;Hwang, Joon-Hyun
    • Proceedings of the KIEE Conference
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    • pp.727-728
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    • 2008
  • This paper deals with characteristic analysis of permanent magnet synchronous motor with full-ring magnet. The modeling of magnetic circuit is performed analytically. And then, analytical solution for open-circuit field distribution due to permanent magnet, back-EMF and torque are derived in terms of magnetic vector potential and two-dimensional polar coordinate system. The analytical results are validated extensively by finite element analyses. Finally, we performed experiments of permanent magnet synchronous motor with full-ring magnet.

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Thrust Hybrid Magnetic Bearing using Axially Magnetized Ring Magnet

  • Park, Cheol Hoon;Choi, Sang Kyu;Ahn, Ji Hoon;Ham, Sang Yong;Kim, Soohyun
    • Journal of Magnetics
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    • v.18 no.3
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    • pp.302-307
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    • 2013
  • Hybrid-type magnetic bearings using both permanent magnets and electromagnets have been used for rotating machinery. In the case of conventional thrust hybrid magnetic bearings supporting axial loads, radially magnetized permanent ring magnets, which have several demerits such as difficult magnetization and assembly, have been used to generate bias flux. In this study, a novel thrust hybrid magnetic bearing using an axially magnetized permanent ring magnet is presented. Because it is easy to magnetize a ring magnet in the axial direction, the segmentation of the ring magnet for magnetization is not required and the assembly process can be simplified. For verifying the performance of the proposed method, a test rig that consists of a proposed thrust magnetic bearing and variable loads is constructed. This paper presents the detailed design procedures and the obtained experimental results. The results show that the developed thrust magnetic bearing has the potential to replace conventional thrust magnetic bearings.

Numerical Analysis of Moving Type and Static Type Electrodynamic Suspension Simulator with Superconducting Levitation Magnet (초전도 부상자석을 이용한 동적 및 정지형 반발식 자기부상 시험기의 수치해석)

  • Lee, E.R.;Bae, D.K.;Chung, Y.D.;Yoon, Y.S.;Ko, T.K.
    • Progress in Superconductivity and Cryogenics
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    • v.11 no.1
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    • pp.49-54
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    • 2009
  • This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator and static type EDS simulator using high-Tc superconducting (HTS) levitation magnet. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible two ways to simulate the EDS system were simulated in this paper by using finite element method (FEM). The first way was the moving type simulator which consists of the fixed HTS magnet and the moving ground conductor. The second way was the static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

KICKER MAGNET MODULATOR IN PLS (포항방사광가속기 킼커 대출력 펄스전원장치)

  • Nam, S.H.;Jeong, S.H.;Han, S.H.;Suh, J.H.;Ha, K.M.
    • Proceedings of the KIEE Conference
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    • pp.1779-1781
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    • 1997
  • The 2.0 GeV Pohang Light Source (PLS) is consisted of a full energy Linac and a storage ring. Four kicker magnets are installed in the storage ring tunnel to move the stored beam orbit in the storage ring closer to the injected beam from the beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. A kicker magnet modulator drives all four kicker magnets to maintain field balance and also synchronized kick of the beam. The kicker modulator can handle 2 GeV full energy beam. The kicker magnet modulator is installed in the storage ring tunnel and under stable operation. Specification of the kicker magnet modulator is ${\sim}6.0{\mu}s$ pulse-width, 200 ns flat-top width with ${\pm}0.2%$ regulation, ${\sim}24\;kA$ peak current, and 10 Hz repetition rate. Two thyratron switches (EEV CX-1536AX) are used in the system. In this article, design, and experimental results of the kicker magnet modulator are discussed.

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Design and Implementation of Portable NMR Probe Magnet

  • Junxia, Gao;Yiming, Zhang;Jiashen, Tian
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.14-22
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    • 2017
  • The NMR's probe consists of the static magnetic field generator (magnetic source) and the RF coil. It is very strict for the homogeneity of the static magnetic field intensity of the magnetic source, so the cost of the magnetic source is more expensive in the entire nuclear magnetic resonance instrument. The magnetic source generally consists of electromagnet, permanent magnet and superconducting magnet. The permanent magnet basically needs not to spend on operation and maintenance and its cost of manufacture is much cheaper than the superconducting magnet. Therefore, the permanent magnet may be the only choice for the static magnetic field device if we want to use the magnetic resonance instrument as an analyzer for production by reducing price. A new probe magnet was developed on the basis of the permanent magnet ring in this paper to provide a technological way for reducing the manufacturing cost, weight and volume of the existing nuclear magnetic resonance instrument (including MRI) probe.

A New Type of CPPM Machine with Stator Axial Magnetic Ring

  • Xie, Kun;Li, Xinhua;Ma, Jimin;Wu, Xiaojiang;Yi, Hong;Hu, Gangyi
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1285-1293
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    • 2018
  • This paper proposes a new type of consequent-pole permanent-magnet (CPPM) machine with stator axial magnetic ring that increases torque capability over a wide speed range and enhances efficiency for the built-in rare-earth permanent magnet synchronous machine used in new energy vehicles. The excitation winding of the CPPM hybrid excitation synchronous machine in the stator is replaced by ferrite magnetic ring to simplify the structure and manufacturing process of the machine. The basic structure and magnetic regulation principle of the proposed machine are introduced and compared with the traditional interior rare-earth permanent magnet synchronous machine and CPPM hybrid excitation synchronous machine. Finally, experimental results of a new type of CPPM synchronous motor prototype with axial magnetic ring are introduced in the paper.

Magnetic Measurement of PLS Storage Ring Prototype Dipole Magnet (방사광 가속기용 2극 전자석 특성측정 및 보정)

  • 강봉구;박기현;윤종렬;구양모
    • Journal of the Korean Magnetics Society
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    • v.2 no.2
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    • pp.163-168
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    • 1992
  • Results of magnetic measurement of a prototype Storage Ring dipole magnet for the Pohang Light Source (PLS) are summarized. Hall probe mapping and rotating coil methods are used to measure field profiles and integrated field properties. End chamfering experiments are performed on the as-built magnet, which has four removable pole-end pieces, to meet the specifications set from beam dy-namics requirement. The corrected magnet has efficiency of 99.7% at 2.0 GeV excitation ad higher order multipole error levels less than the specifications for all excitations, showing that the magnet has appropriate properties for the PLS Storage Ring.

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The Development of PLS-II Storage-ring Girder Systems at PAL (방사광 가속기 PLS-II 저장링 거더 시스템 개발)

  • Kim, Seungnam;Lee, Chaesun;Lee, Honggi;Kim, Kwangwoo;Nam, Sanghun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.8
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    • pp.690-697
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    • 2013
  • The magnets and vacuum chambers, which are the main facilities of the Pohang light source are installed on the storage-ring girders. System safety and reliability should be taken into account for the precise operating of the main facilities, so vibration analysis is essential to do this. Static and seismic analyses were performed for the design of structure considering safety, and also frequency and response spectrum analyses were performed for the precise alignment. With these results, the effects of surrounding vibration were checked. This paper explains about the design and vibration analysis of girder systems.

Fabrication of the (Alnico, Sm-Co) Bonded Magnet and its Magnetic Properties ((알니코, 사마리움-코발트) 본드자석의 제조 및 자기적 특성연구)

  • Kim, Jung-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.12
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    • pp.988-995
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    • 2010
  • In this study the (Alnico, Sm-Co) bonded magnets were fabricated by mixing the Sm-Co added alnico alloy powders with epoxy resin and binder, appropriately. Also, the hybrid ring magnets of (Alnico, Sm-Co)/Sr-ferrite were fabricated by coupling the Sr-ferrite composite layer with an (Alnico, Sm-Co) magnet. The magnetic properties of (Alnico, Sm-Co) ring magnets were varied with the amount of Sm-Co powders. The addition of Sm-Co powders increased a remanent induction($B_r$) and coercive force($_BH_C$), while decreasing a surface flux density and repulsive distance. The surface flux density and repulsive distance for the (Alnico, Sm-Co) ring magnet increased with a magnetizing voltage up to about 160 V and reached an apparent saturation point. Also, the measurements of temperature and moisture characteristics showed that the surface flux densities of N-S poles and repulsive distance decreased a little within 4% after 10 days passed.

Analysis on the Characteristics of the Superconducting Electrodynamic Suspension According to the Variation of the Ground Conductor (지상도체 변화에 따른 초전도 반발식 자기부상 특성 해석)

  • Bae, Duck-Kweon;Cho, Han-Wook;Lee, Jong-Min;Han, Hyung-Suk;Lee, Chang-Young;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • pp.1159_1160
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    • 2009
  • This paper presents the numerical simulation results on the supercodnucting electrodynamic suspension (EDS) simulator according to the variation of the ground conductor. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible way to simulate the EDS system were simulated in this paper by using finite element method (FEM). The static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

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