Levitation Force Relaxation of HTS Bulk above NdFeB Guideways at Different Approaching Speeds

• Published in: Journal of superconductivity and novel magnetism Vol. 22; no. 5; pp. 511 - 516
• Main Authors: Qin, Yujie, Lu, Yiyun, Wang, Suyu, Wang, Jiasu
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-07-2009; Springer
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic Materials; Magnetic properties; Magnetism; Original Paper; Physics; Physics and Astronomy; Properties of type I and type II superconductors; Strongly Correlated Systems; Superconductivity; Levitation relaxation; High-temperature superconductors; 85.25.-j; Different speeds; Permanent magnetic guideway; Railroad cars; High-Tc superconductors; Guideway; Permanent magnets; Barium Copper Yttrium Oxides Mixed; Magnetic levitation
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-009-0449-x

The zero-field cooling levitation force relaxation of the YBCO bulk above two types of NdFeB guideways, which were used in the high-temperature superconducting maglev vehicle system, was studied experimentally when the bulk moved towards the guideways at different speeds. In this experiment, a sample with the diameter of 50 mm and thickness of 15 mm was used; the time range in the relaxation measurements was from 0 s to 200 s. As a result, a nearly linear logarithmic decay of the levitation forces with time was observed. It was found that the influence of the approaching speeds on the levitation force relaxation is different, and that the levitation force decay is closely related to the guideway structures. Based on the monopole peak PMG, the approaching speeds will influence more the levitation force decay than the multipole Halbach. So the maglev vehicle above mutipole Halbach structure PMG will work more stably than that above the monopole peak PMG.