9.4 HTS FESS principle model Ë 349plate made of epoxy resin with diameter of 500 mm. The upper and lower ASBs are
fixed at both ends of a vertical shaft to suspend and levitate the shaft. At the middle of
the shaft, an inductive motor is mounted to drive the rotational rotor. The working
gap of this motor is 2.5 mm, which can realize the fully stable levitation of ASBs.
A transformer is used to control the motor by changing the voltage of the power
supply, as shown in Fig. 9.13. The maximum rotational speed of the motor is about
3000 rpm.
The two axial ASBs are the core part of the system. One of them is used to
levitate and the other is used to suspend the rotor. Both HTS stators are independently
composed of seven single-domain melt-textured YBCO bulks with diameter of 30 mm
and height of 18 mm (as shown in Fig. 9.14) and the PM rotors are both made of three
cylindrical axial-magnetized NdFeB PMs by superposition (as shown in Fig. 9.15). Each
PM is 63 mm in diameter and 9 mm in height and its maximum surface magnetic field
Fig. 9.13:Photo of the double ASBs system model in free rotation with a transformer.
Fig. 9.14:Photo of HTS (YBCO) stator of ASB.