206 Ë 6 First manned HTS Maglev vehicle in the world
Tab. 6.16:Horizontal magnetic field distribution at height of 25 mm above the PMG [29].
Horizontal position (mm) − 2 0 2 4 6 8 10
FieldB(T) 0. 354 0. 354 0. 354 0. 349 0. 342 0. 332 0. 322
Horizontal position (mm) 12 14 16 18 20 22 24
FieldB(T) 0. 310 0. 295 0. 281 0. 266 0. 251 0. 220 0. 205
the above measurement may not be accurate. The maximum guidance force should
be an instantaneous explosive force which maintained the original position. When a
sudden impact force acted on the Maglev vehicle system, the guidance forces were not
reflected with the above slow measurement rate. Perhaps the relaxation had ceased to
exist in this emergency, because the impact had already ended before relaxation can
occur.
Trapped flux was 0.220 T for a FCH of 42 mm. If both the trapped flux and surface
magnetic field of the PMG did not change during the measuring process of the
guidance forces, the measured guidance forces were the magnetic attractive forces
between the trapped flux of 0.220 T and magnetic field of PMG. In a certain range,
the guidance forces gradually increased with the increase of horizontal displacement,
but beyond this range it was not attractive, i.e. the measurement guidance force was
zero (in fact, the guidance force of the original position was an objective existence
value). Table 6.16 lists the horizontal magnetic field distribution at a levitation height
of 25 mm above the PMG. The levitation height of 25 mm can be used as a reference
in the analysis of the experimental data at the levitation height of 26 mm. However,
the surface magnetic field of the PMG was smaller and smaller with the increase
of the horizontal displacement. The effect of the horizontal displacement on the
guidance forces was much larger than that of the horizontal field change on the PMG
surface.
In order to research the true effective guidance forces at certain lateral displace-
ment, the guidance forces were measured while gradually increasing the maximum
lateral displacement [61]. Figure 6.72 shows the experimental results of the guidance
forces of the entire vehicle under different maximum lateral displacement.
Figure 6.72 shows that the vehicle could return to the initial position after the
horizontal lateral forces were removed at the maximum lateral displacement of 2 mm.
The vehicle could not return to the initial position after the horizontal lateral forces
were removed at the maximum lateral displacement of 4 mm. There was separation
between the force sensor and the propulsion system at a lateral displacement of 1 mm.
In the operating state, the effective lateral displacement of the vehicle was less than
4 mm. The guidance force at a vehicle lateral displacement of 4 mm was 377 N. The
guidance force at a vehicle lateral displacement of 6 mm was 524 N. Thus, it can be seen
that the guidance forces increased with the increase of lateral displacement; however,
these are the above-mentioned pseudo-guidance forces.