Maximum Limit of Superconducting Persistent Current for Superconducting Magnetic Suspension System

Superconducting technique is applied to a superconducting magnetic suspension system. The suspension system is composed of a superconducting coil, a copper coil, a suspended object, a photo sensor, a PID controller, and power amplifiers. Persistent current in a superconducting coil and control current in a copper coil are used for suspending object and controlling object, respectively. In this paper, large-gap trial on the system is performed, and the static and dynamic characteristics of the suspended object are performed. As a result, it is found that the suspended object continues to suspend at a distance 43 mm for ≈14 s. It is found that there is a maximum limit of superconducting persistent current for the system. The details of the superconducting persistent current are discussed. This may be the first trial that superconducting persistent current is used for a magnetic suspension system.