A Novel Magnetic Bearing Using REBCO Double Crossed Loop Coils

The superconducting magnetic bearing ability to sustain a stable levitation gap without a control system is its main advantage and finds an application niche on urban transportation, as demonstrated by the Maglev Cobra project. However, the use of YBCO bulks brings major drawbacks, such as the absence of a quality-standard large scale production process, hampering this application to further advance into commercialization. On the other hand, REBCO tapes have reached large scale production worldwide and have surpassed bulks in critical currents and pinning capacities, making them a possible substitute for bulks in large scale applications. This paper proposes a novel superconducting magnetic bearing made of REBCO tapes. The bearing here proposed uses tape segments, with partially opened slits, to form superconducting jointless loops. This allows larger flux linkage and thus provides larger levitation forces than stacked segments. Multiple loops are stacked side by side to form two symmetrical coils, with better volume usage than a single loop coil. Simulations are carried out to foresee the levitation force behavior. Force measurements are made in order to evaluate the new bearing performance with the Maglev Cobra permanent magnet guideway. The results reinforce the thesis that tapes could substitute bulks in superconducting magnetic bearings.