Testing and Comparison of Levitation Forces and Rotational Friction in Different Superconducting Tape Stacks

High-temperature superconducting (HTS) tape stacks have broad applications in magnetic levitation because of the uniform induced current distribution, good heat dissipation, and preferable mechanical properties. Configuration of the stack is one of the primary factors on the uniformity and strength of the trapped magnetic field. In this paper, the levitation characteristics, which are levitation force, stiffness, and rotational friction of four different YBCO tape stack configurations, were compared. It is observed from the experiments that there is an obvious influence of stack configurations on the levitation characteristics. The levitation forces gradually improve with the increase of tape pieces. While the module No.2 is an inclined stack, the levitation force is related to the inclination angle. Most of the tape stack modules can give low loss rotation in levitation, and the magnitude of the friction coefficient is close to 10^{− 6}. By the investigation of levitation characteristics, the tape stack has great potential for the bearing application.