Abstract
We present the dependence of lift and stability on the arrangement of multiple HTS bulks in an active-maglev system composed of HTS bulks and an electromagnet. We experimentally investigated the influence of asymmetric magnetic field distribution in a field-cooling process on the characteristics of levitation such as levitation force and stable-levitation region. In spite of unstable levitation, levitation force was increased with the distance between the axes of the bulk and electromagnet. It may be considered that unstable levitation is caused by asymmetric supercurrent distribution within the bulk. We investigated a suitable arrangement of multiple HTS bulks in an active-maglev system experimentally. Levitation force was measured in four types of multiple-bulk arrangements. It was revealed in the experiment that the levitation force was influenced by the distance between the bulks and that the maximum levitation force was obtained when the bulks were located near the inner boundary of the electromagnet windings. It is believed that the most suitable arrangement is closely related to magnetic field distribution; i.e. electromagnet dimensions (inner and outer radii, thickness).
