178 Ë 6 First manned HTS Maglev vehicle in the world
Tab. 6.9:Parameters measured for HTS bulks over the PMG [43].
Samples diameter (mm) Thickness (mm) Mass (g) Samples from
TG186/20 26.6 9. 2 32.2 IFW
BJ218 30.0 16 69.7 GRINM
TG177/6 49.0 14. 8 169.3 IFW
Figure 6.31 shows the measured results of the guidance forces of each sample for a
15-mm FCH [43]. The arrow direction represents the testing process from the original
location to the maximum lateral displacement, 20 mm, from which it would return
to the starting position. Guidance forces increase rapidly with increasing sample
diameter, while guidance forces hysteresis become more and more obvious, but the
return distance decreases with the increase of diameter.
Taking into account the three samples with different thicknesses, the influence of
sample size on the experimental results of guidance forces is not accurately reflected
by Fig. 6.31. In addition, another factor reducing the accuracy of conclusions based
on these results was inconsistent variations in the physical properties of the samples.
6.9.3Influence of HTS bulk thickness on the properties
Zhu et al. [39] investigated experimentally the influence of HTS YBCO bulk thickness
on the levitation properties. In this experiment, a HTS bulk sample with a diameter
Fig. 6.31:Guidance forces vs. lateral displacement of three samples over the NdFeB PMG
at 77 K [43].