330 Ë 9 HTS Maglev bearing and flywheel energy storage system
Fig. 9.2:Axial force measurement device for RSB prototype: (a) schematic view and (b) photograph.
(1) DC motor. (2) Axial force sensor of the SCML-02 measurement system. (3) Epoxy resin board.
(4) Mechanical bearing. (5) Dewar. (6) Liquid nitrogen. (7) PM rotor. (8) HTS stator. (9) Spindle.
of 13× 32 ×64 mm. The working gap of HTSB was 1.5 mm. The PM rotor was composed
of PM rings and iron rings with five magnetic poles (Fig. 9.3a). The magnetic field of
the central pole at the surface of the PM rotor was 1.34 T (Fig. 9.3b) and the magnetic
field decreases with the increasing distance away from the PM rotor. At the position
of 11 mm away from the PM rotor, magnetic field was less than 0.2 T. This RSB was
manufactured to study the axial stiffness at different rotational speeds. As shown in
Fig. 9.2b, the axial force measurement device included a RSB, a Dewar, a DC motor,
a DC power supply, a tachometer and a transmission mechanism. This measurement
device was installed in the HTS Maglev measurement system SCML-02 [34] (see Section
5.5). The Dewar with a HTS stator inside was fixed on anX-Ymotion stage, and the
Fig. 9.3:PM rotor: (a) photograph of PM rotor, the arrows in the PM rings show the magnetization
directions Schematically, and (b) magnetic field at the center pole of the PM rotor at different
distances from the PM rotor.