• Title/Summary/Keyword: racetrack type coils

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A study on charging and electrical stability characteristics with no-insulation and metal insulation in form of racetrack type coils

  • Quach, Huu Luong;Kim, Ho Min
    • Progress in Superconductivity and Cryogenics
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    • v.22 no.3
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    • pp.13-19
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    • 2020
  • This study presents the experiment and simulation results on the magnetic field response and electrical stability behaviors of no-insulation (NI) and metal insulation with stainless steel tape (MI-SS) which wound in form of racetrack type coils. First of all, the structural design of the racetrack type bobbin was shown along with its parameters. Then, the current-voltage tests were carried out to measure the critical current of both test coils. Also, the sudden discharging and charging tests were performed in the steady state to estimate the decay field time and magnetic field response, respectively. Finally, the overcurrent tests were conducted in the transient state to investigate the electrical stability of these test coils. Based on the experimental results, the contact surface resistances were calculated and applied to the field coils (FCs) of 10-MW-class second generation high temperature superconducting generator (2G HTSG) used in wind offshore environment. The charging delay time and electrical stability for NI and MI-SS HTS FCs of 10-MW-class 2G HTSG are analyzed by the equivalent circuit model and the key parameters which were obtained from the electromagnetic finite element analysis results.

A Study on Thermal Stability of the Non-insulated HTS Racetrack-type Coil Under Various External Pressures Applied to Straight Sections (무절연 고온 초전도 레이스트랙형 코일의 직선구간 압력변화에 따른 열적 안정성 연구)

  • Kwon, O.J.;Kim, K.L.;Choi, Y.H.;Yang, D.G.;Kim, Y.G.;Lee, T.S.;Ko, T.K.;Lee, H.G.
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.3
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    • pp.33-37
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    • 2012
  • An HTS racetrack-type coil without turn-to-turn insulation was characterized by critical current, sudden discharge, and over-current tests with respect to external pressures applied to the straight sections of the coil. The thermal stability of the non-insulated HTS racetrack-type coil was remarkably enhanced with increasing external pressure applied to the straight sections of racetrack-type coil. Furthermore, over-current test results confirmed that the non-insulated HTS racetrack-type coil with increased turn-to-turn thermal contact has the potential to be manufactured into field coils of HTS wind turbine generators with highly enhanced thermal and electrical stabilities.

Investigation of Acoustic Emission Signals in Racetrack Superconducting Field Winding Coils (레이스트랙형 초전도계자코일의 AE 신호 특성평가)

  • Sohn, M.H.;Baik, S.K.;Ko, R.K.;Lee, E.Y.;Bae, J.H.;Kwon, Y.K.;Ryu, K.S.
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.186-188
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    • 1998
  • Acoustic emission monitoring on two racetrack superconducting field winding coil was performed during excitation and quenches to diagnose the integrity of the field winding coils. Two field windings were not impregnated with epoxy The results confirm that the acoustic emission signals are mainly due to conductor motions which cause premature quenching of the winding. The quench current of modified racetrack type field winding coil (Type B) are more higher than that of conventional field winding coil (Type A).

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Design and Fabrication of Racetrack type High Tc Superconducting Magnet for the Superconducting Rotating Machine (초전도회전기용 래이스트랙형 고온초전도 마그네트 설계 및 제작)

  • Sohn, M.H.;Baik, S.K.;Jo, Y.S.;Lee, E.Y.;Kwon, Y.K.;Ryu, K.S.
    • Proceedings of the KIEE Conference
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    • 2001.04a
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    • pp.3-5
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    • 2001
  • Racetrack coils are used in many areas of superconductivity applications such as generators, motors, maglev, wiggler magnets and so on. The fabrication and characteristics of race-track type High Tc Superconducting (HTS) magnets were carried out. The Magnet is composed of 3 pancake coils wound by 37-filamental Bi-2223/ Ag-alloy tapes. Quench current ($I_q$) of both whole magnet and 3 pancake coils were measured. At 77K under the self-field, $I_q$ of magnet was 12A, while in the case of middle pancake coil, $I_q$ was 15A. The upper pancake coils of racetrack magnet with iron plates, magnet having optimized current distribution and initial magnet are compared with each other through 3D FEA, manufacturing and testing these magnets. The measured performance of the upper pancake coil #3 with iron plates improved by 50% on the basis of initial pancake coil #3. Quench current ($I_q$) of field winding was 12A. In addition, the fabrication processes and the characteristics of HTS magnet are described.

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