272 Ë 8 New progress of HTS Maglev vehicle
Fig. 8.11:Schematic diagram of the YBCO bulks array above the PMG in SCML-03.
Fig. 8.12:Levitation forces and their average result during the step-by-step acceleration and
deceleration.
attenuation over 60 km/h, the transition among all velocity parts of the curve was
smooth. The force attenuation mainly appeared at speeds less than 60 km/h. It has
been reported that the diffusion of the shielding current caused by an AC field might be
restricted at high frequency and then rarely penetrate deeper [24]. Therefore, the rea-
sonable explanation is that the total shielding current attenuation due to the field per-
turbation caused by the motion above PMG might also be restrained at high velocities
so that the force attenuation saturated with speeding up. Thus, the force attenuation