Increase of Levitation Force due to Soft Ferromagnetic Plate and Bar in Magnetic Levitation System Using GdBCO Bulk

We have studied a magnetic levitation system using a magnetic shielding effect of a high-temperature superconducting (HTS) bulk. The basic system is composed of a soft ferromagnetic bar, the HTS bulk, and a permanent magnet. To increase levitation force, we proposed two kinds of modified systems. One is that two basic systems are placed side by side. We name this the “2-set model.” The other is that two basic systems are commented with a common soft ferromagnetic bar. This system is called the “common bar model.” We experimentally obtained the levitation force of the modified systems. According to the experiments, the levitation force of the “2-set model” and the “common bar model” were 314 and 327%, respectively, of that of the basic model. We also numerically analyzed the magnetic flux distribution of the modified systems. From the analysis, the soft ferromagnetic bar and plate were effective to reduce magnetic resistance in a magnetic circuit of the systems, and hence, the levitation force became large.