An Improved Starting Strategy for a Spherical Superconducting Rotor

Due to the absence of friction, a superconducting rotor can achieve a very high speed to obtain a large angular momentum for high-precision measurement of the angular displacement and angular velocity. However, in practice, the superconducting rotor will do vibration and collide with the inner wall of the rotor cavity at a certain speed during startup, which will result in the failure of the rotor's acceleration. In this paper, an improved starting strategy was proposed. This new method can avoid the peak of vibration amplitude by changing the bearing stiffness of the rotor quickly. The startup and shutdown process of the rotor was redesigned. Several experiments were carried out to verify its correctness. The results show that the superconducting rotor can be accelerated to the rated speed of 200 Hz (12 000 r/min) successfully by the proposed method. Furthermore, the start time of the rotor was greatly reduced to 20 minutes from more than one hour for the original method.