Low rotational drag in high-temperature superconducting bearings

Hull, J.R.; Mulcahy, T. M.; Uherka, K.L.; Abboud, R.G.

doi:10.1109/77.402628

Cited by 100 publications

(36 citation statements)

References 15 publications

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“…Another set of spin-down measurements at 77 K were conducted in a liquid nitrogen cryostat (LNC) with the apparatus described by Hull et al [30]. This apparatus was designed to minimize energy losses due to eddy currents.…”

Section: Tests Results and Interpretationmentioning

confidence: 99%

“…In all measurements the rotor consisted of the magnet without the HWP. We quantify the results of the spin-down measurements in terms of the coefficient of friction (COF) [30] given by…”

Section: Tests Results and Interpretationmentioning

confidence: 99%

“…The coefficient a 0 has been interpreted as the contribution of hysteresis to the angular acceleration and a 1 quantifies the contributions from eddy currents and ambient pressure [30]. If a 1 is non-zero then f should be an exponential function of time.…”

Section: Tests Results and Interpretationmentioning

confidence: 99%

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A cosmic microwave background radiation polarimeter using superconducting bearings

Hanany

Matsumura

Johnson

et al. 2003

IEEE Trans. Appl. Supercond.

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Abstract-Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ringshaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured the coefficient of friction as a function of several parameters including temperature between 15 and 80 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm, and ambient pressure between 10 −7 and 1 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

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Section: Tests Results and Interpretationmentioning

confidence: 99%

“…In all measurements the rotor consisted of the magnet without the HWP. We quantify the results of the spin-down measurements in terms of the coefficient of friction (COF) [30] given by…”

Section: Tests Results and Interpretationmentioning

confidence: 99%

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A cosmic microwave background radiation polarimeter using superconducting bearings

Hanany

Matsumura

Johnson

et al. 2003

IEEE Trans. Appl. Supercond.

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“…Fig In the experimental procedures we have used either the free spin down measurements [51,54,55] or phase difference detecting [50][51][52]. The first technique was used by Hull et al [54][55][56] in the investigations of the flywheel behaviour to determine the coefficient of friction (COF). Exploiting such a procedure, for the energy loss we can write [51]:…”

Section: Magnetic Rotormentioning

confidence: 99%

Magnetic Flux Dynamics in HTS Bulks with Levitation Techniques

et al. 2002

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The discovery of high-temperature superconductors (HTS) has led to understanding that, in order to explain and utilize the phenomenon, completely new physical approaches should be introduced at all scales: microscopic, mesoscopic, macroscopic. Leaving first two scales beyond the scope of the present paper, we focus in the upper limit of the last scale, the study of the magnetic flux dynamics in HTS bulks-the dynamics of the 'compact vortex structures'. A new direction in the experimental superconducting physics, the investigation of HTS bulks with levitation techniques, which has been elaborated during last years to effectively explore the subject, as well as the new fundamental and applied results obtained there from are overviewed here.Відкриття високотемпературних надпровідників (ВТНП) призвело до розуміння то-го, що задля пояснення та використання цього явища на всіх рівнях: мікроскопічно-му, мезоскопічному та макроскопічному, має бути створено принципово нові фізичні підходи. Полишаючи перші два рівні поза увагою даної роботи, ми детально розгля-даємо верхню границю останнього -дослідження динаміки магнітного потоку в масивних ВТНП, динаміки «компактових вихорових структур». Дана робота -це огляд нового напрямку експериментальної фізики надпровідників -дослідження масивних ВТНП левітаційними методами -що його було вироблено останнім часом для вивчення зазначеної проблеми, а також тих нових фундаментальних та практич-них результатів, що було тут отримано.Открытие высокотемпературных сверхпроводников (ВТСП) привело к пониманию того, что для объяснения и использования этого явления необходимо создание принципиально новых физических подходов на всех уровнях: микроскопическом, мезоскопическом, макроскопическом. Оставляя первые два уровня за рамками данной работы, мы сфокусировали внимание на верхнем пределе последнего -исследовании динамики магнитного потока в массивных ВТСП, динамики «ком-пактных вихревых структур». Данная работа -это обзор нового направления экс-периментальной физики сверхпроводников, которое было выработано за послед- Fiz. Met. 2002, т. 3, сс. 357-386 Оттиски доступны непосредственно от издателя Фотокопирование разрешено только в соответствии с лицензией 2002 ИМФ (Институт металлофизики им. Г. В. Курдюмова НАН Украины) Напечатано в Украине. 358A. A. Kordyuk, V. V. Nemoshkalenko , A. I. Plyushchay, and R. V. Viznichenko ние годы, а также тех новых фундаментальных и прикладных результатов, которые были здесь получены.

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“…The SFES using a superconductor magnetic bearing (SMB) [1,2] is a environment-friendly utility without chemicals and has higher energy storage efficiency than other type flywheels using a mechanical ball bearing and a magnetic bearing. The energy loss characteristics and efficiency of a SFES using SMB have been evaluated in many studies [3][4][5][6]. The SFES shows a small amount of loss caused by the inhomogeneous magnetic field of a superconductor.…”

Section: Introductionmentioning

confidence: 99%

Experimental Estimation on Magnetic Friction of Superconductor Flywheel Energy Storage System

Lee¹,

Han²,

Park³

2011

Journal of Magnetics

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This study estimated experimentally the loss distribution caused by magnetic friction in magnetic parts of a superconductor flywheel energy storage system (SFES) to obtain information for the design of high efficiency SFES. Through the spin down experiment using the manufactured vertical shaft type SFES with a journal type superconductor magnetic bearing (SMB), the coefficients of friction by the SMB, the stator core of permanent magnet synchronous motor/generator (PMSM/G), and the leakage flux of the metal parts were calculated. The coefficients of friction by the stator core of PMSM/G in case of using Si-steel and an amorphous core were calculated. The energy loss by magnetic friction in the stator core of PMSM/G was much larger than that in the other parts. The level of friction loss could be reduced dramatically using an amorphous core. Energy loss by the leakage magnetic field was small. On the other hand, the energy loss could be increased under other conditions according to the type of metal nearby the leakage magnetic fields. In manufactured SFES, the rotational loss by the amorphous core was approximately 2 times the loss of the superconductor and leakage. Moreover, the rotational loss by the Si-steel core is approximately 3~3.5 times the loss of superconductor and leakage.

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Low rotational drag in high-temperature superconducting bearings

Abstract: Bearings consisting of permanent magnets stably levitated over high-temperature superconductors exhibit low rotational drag and

Cited by 100 publications

References 15 publications

A cosmic microwave background radiation polarimeter using superconducting bearings

A cosmic microwave background radiation polarimeter using superconducting bearings

Magnetic Flux Dynamics in HTS Bulks with Levitation Techniques

Experimental Estimation on Magnetic Friction of Superconductor Flywheel Energy Storage System

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