Numerical Evaluation of Rotational Speed Degradation in the Superconducting Magnetic Bearing for Various Superconducting Bulk Shapes

Masaie, Issei; Demachi, Kazuyuki; Ichihara, T.; Uesaka, Mitsuru

doi:10.1109/tasc.2005.849625

Cited by 23 publications

(8 citation statements)

References 5 publications

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“…Therefore, the axial displacement linked with the tilt is the main reason for exponential dependence. A similar exponential dependence over an axial displacement of a rotating bearing was also shown in [6].…”

Section: Resultssupporting

confidence: 72%

“…Friction free superconducting bearings are suitable for high-speed applications, which include linear as well as rotational setups, as shown by many groups in recent years [1][2][3][4][5]. Although there is no mechanical friction in the bearing, other dissipating losses might be generated [6][7][8][9]. For rotating applications these losses are highly depended on the rotational speed [10][11][12], on the spatial displacements [13] and the magnet quality [14].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dependency of hysteretic loss on speed and tilt in a rotating superconducting magnetic bearing

Espenhahn

Sparing

Berger

et al. 2021

Supercond. Sci. Technol.

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Superconducting magnetic bearings enable friction-free rotation, which is beneficial for different applications. Whereas mechanical losses are drastically reduced, additional hysteretic losses might be generated as for example by a process-related tilt of the field-cooled permanent magnet of the superconducting bearing. We designed a caloric measurement setup with a resolution down to 5 mW in order to study such losses in more detail. Therefore, a field-cooled magnet ring is deliberately tilted up to 3° before it rotates with a speed of up to 5000 rpm above the superconducting ring. The generated losses inside the superconductor lead to an increased evaporation rate in the attached liquid nitrogen bath, which in turn results to a measurable volume flow. The determined losses increase almost linear with speed, whereas an exponential increase was observed for the tilt angle. The results were confirmed by 2D simulations using a two-component model leading to similar dependencies for the hystertic losses on speed and tilt.

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Section: Resultssupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Dependency of hysteretic loss on speed and tilt in a rotating superconducting magnetic bearing

Espenhahn

Sparing

Berger

et al. 2021

Supercond. Sci. Technol.

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“…The SFES shows a small amount of loss caused by the inhomogeneous magnetic field of a superconductor. On the other hand, energy loss by magnetic friction during rotation is increased because the SFES has magnetic fields in some parts, such as the SMB [4,7] permanent Magnet type Synchronous motor/generator (PMSM/G) [8], and windage loss depending on the degree of vacuum. Since the energy loss at the degrees of vacuum under 1E −4 [torr] can be ignored [2], the total energy loss of the SFES can be reduced significantly if the losses by the SMB and PMSM/G can be reduced [8].…”

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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“…The HTS bearings, which offer dynamic stability without the use of active control, are the key technology that distinguishes the SFES from other flywheel energy storage devices [5][6][7][8]. During the operation of the SFES, the system shows unstable running conditions due to unpredictable factors, which lead to lower operation efficiency [9]. These unpredictable factors must be controlled through the optimal design of superconductor bearings.…”

Section: Introductionmentioning

confidence: 99%

Static properties of high temperature superconductor bearings for a 10kWh class superconductor flywheel energy storage system

Park

Han

Jung

et al. 2010

Physica C: Superconductivity and its Applications

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Numerical Evaluation of Rotational Speed Degradation in the Superconducting Magnetic Bearing for Various Superconducting Bulk Shapes

Cited by 23 publications

References 5 publications

Dependency of hysteretic loss on speed and tilt in a rotating superconducting magnetic bearing

Dependency of hysteretic loss on speed and tilt in a rotating superconducting magnetic bearing

Experimental Estimation on Magnetic Friction of Superconductor Flywheel Energy Storage System

Static properties of high temperature superconductor bearings for a 10kWh class superconductor flywheel energy storage system

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