Effect of assembled bar magnet configuration on levitation force of single domain GdBCO bulk superconductor

The effects of magnetization methods with additional permanent magnet on the magnetic field distribution and the levitation force of single domain GdBCO bulk superconductor are investigated with a cubic permanent magnet in their coaxial configuration in zero field cooled state at liquid nitrogen temperature in three different ways. It is found that when the N pole of the cubic permanent magnet, for the levitation force measurement, is placed above the GdBCO bulk superconductor and in the downward direction, the maximal levitation force can be improved to 31.8 N, and that when the N pole of the additional cubic permanent magnet points to upward and sticks to the bottom of the GdBCO bulk, the maximal levitation force is increased up to about 222% of the levitation force of 14.3 N for the system without additional permanent magnet. The maximal levitation force can be improved to 21.6 N (or reduced to 8.6 N), when the GdBCO bulk superconductor is closely placed below and magnetized by the additional cubic permanent magnet with N pole in the upward (or downward) direction, and the additional permanent magnet is removed away after the magnetization, the maximal levitation force is about 151% (or 60%) of 14.3 N for the system without the additional permanent magnet. The results indicate that the levitation force of high temperature bulk superconductors can be effectively improved by introducing additional permanent magnet based on the scientific and reasonable designing of the system configurations, which is very important for the practical design and application of superconducting magnetic levitation system.

The effects of magnetization methods with additional permanent magnet on the magnetic field distribution and levitation force of single domain GdBCO bulk superconductor

Ma¹,

Yang²,

Li³

et al. 2012

The effect of additional permanent magnet magnetizing methods on magnetic field distribution and the levitation force of single domain GdBCO bulk superconductor

Ma¹,

Yang²,

Wang³

et al. 2013

It has been investigated that the interaction force between a cubic permanent magnet PM1 and a GdBCO bulk (HTSC) superconducting permanent magnet (SCPM) magnetized by a cubic permanent magnet PM2 under different configurations at 77 K. Two configurations were used for the magnetization of the GdBCO bulk, one is that the North pole of the PM2 is in upward direction, the other is in downward direction, so that the North pole of the SCPM is in two states SCPM↑ and SCPM↓; the vertical distance between the bottom surface of PM1 and the top surface of SCPM is kept as a constant value, but the PM2 can be fixed at any positions (x) along a diameter of the GdBCO bulk during the magnetization process. It is found that: for the PM1↓-SCPM↑ configuration, the maximum levitation force is increasing from 16.7 N to 23.1 N when x increases from –15 mm to 0, and then decreases to 16.6 N when x further increases to 15 mm; but for the PM1↓-SCPM↓ configuration, the maximum levitation force is decreasing from 17.7 N to 7 N when x increases from –15 mm to 0, and then increases to 17.6 N when x further increases to 15 mm. These results are not only much different in the two configurations, but also much different from the maximum levitation force 17.1 N of the sample under zero field cooled condition, which is closely related with the trapped field distribution of the SCPM at different x values. These results indicate that the levitation force of high temperature bulk superconductors can be effectively improved by introducing additional permanent magnet based on scientific and reasonable designing of the system configurations, which is very important during the practical design and applications of superconducting magnetic levitation systems.

Effect of inner diameter of hollow cylindrical permanent magnet on levitation force of single domain GdBCO bulk superconductor

Ma¹,

Zhang-Long²,

Tao³

et al. 2018

The influence of inner diameter of hollow cylindrical permanent magnet on the levitation force of single domain GdBCO bulk superconductor is investigated by measuring the levitation force between the hollow cylindrical permanent magnet and the single domain GdBCO bulk superconductor. The results show that the levitation force is closely related to the inner diameter of the hollow cylindrical permanent magnet when the inner diameter (d) increases from 0 mm to 26 mm (minimum measuring gap distance Z=2 mm), and all the superconducting magnetic levitation force curve shows magnetic hysteresis phenomenon. With the increase of the inner diameter of the hollow cylindrical permanent magnet, the levitation force at a minimum distance decreases gradually from 14.8 N at d=0 mm to -0.1 N at d=26 mm. The levitation force at the minimum gap distance is negative when d ≥ 20 mm. When 0 mm ≤ dd ≥ 5 mm. The larger magnetic field strength of the superconductor can be obtained, and the levitation force can be effectively improved by the scientific and reasonable designing of the permanent magnet structure. The results have certain guiding significance for designing and optimizing the magnetic suspension bearing system, ring track and superconductor.