A new type of active-maglev system using YBCO bulk and multiple electromagnets

We present a new type of active-maglev system consisting of high-temperature superconducting bulk and multiple electromagnets. A prototype of the new active-maglev system composed of two solenoid type electromagnets located on the same axis was designed. Each electromagnet was operated individually; only the lower electromagnet had been operated until the bulk reached a certain level and then the upper electromagnet was started to operate with a constant current of the lower electromagnet. Lift and levitation height were investigated experimentally as functions of (1) the magnitude of trapped field; (2) the gap between the lower and upper electromagnets; and (3) the levitation height at which the upper electromagnet is started to operate. Independent of these parameters, ’continuous levitation’ in the axial direction was achieved in the new active-maglev system. Electromagnetic behavior within the bulk was also investigated numerically by the finite element method, i.e. axial symmetry field analysis, using the magnetic vector potential. The experimental and computed results imply that levitation height can be remarkably improved by the continuous levitation using multiple electromagnets.