Development of superconducting magnetic bearing with superconducting coil and bulk superconductor for flywheel energy storage system

•We have proposed superconducting (SC) magnetic bearings using SC coil and bulks.•We manufactured a small scale test device based on our concept.•The device levitated a rotor without mechanical contact.•The rotor was rotated contactless over 2000 rpm.•We have demonstrated our SC magnetic bearing feasibility using the device.

We have been developing superconducting magnetic bearing for flywheel energy storage system to be applied to the railway system. The bearing consists of a superconducting coil as a stator and bulk superconductors as a rotor. A flywheel disk connected to the bulk superconductors is suspended contactless by superconducting magnetic bearings (SMBs). We have manufactured a small scale device equipped with the SMB. The flywheel was rotated contactless over 2000 rpm which was a frequency between its rigid body mode and elastic mode. The feasibility of this SMB structure was demonstrated.