274 Ë 8 New progress of HTS Maglev vehicle
Fig. 8.15:Levitation force relaxation after different dynamic measurement cases.
speedup history it had been through. The force decay at 30 km/h seemed to be less
than that at 120 km/h. Although the correction curves were not adopted in this part
for these complex cases, as shown in Fig. 8.15, the levitation force relaxation after
the two different dynamic measurement cases indicated that the forces decreased
more for 30 km/h, and the forces decayed more at low velocities as discussed above.
Meanwhile, the levitation force difference caused by magnetic field history between
the former step-by-step speed-up (indirect, case 1) and the direct speedup (case 2) was
not significant. The levitation force difference between the two velocity groups became
closer with time, less than 10 N at 3300 s.
The levitation force behavior versus levitation gap after the bulk superconductors
were subject to different running cases is displayed in Fig. 8.16. The approaching
part in all curves nearly overlapped with the “directly return” (the quasi-static
Fig. 8.16:Levitation forces vs. levitation gap.