Influence of the Vertical Movement of Bulk on the Levitation Force at Different Temperatures

A ring-shaped YBCO bulk over a Halbach-type guideway as the basic model of Maglev vehicle was used in this paper. The levitation forces of the ring-shaped YBCO bulk, which are combined with vertical round-trip movement times and speeds in the temperature range from 77 to 63 K, were investigated at two different positions, namely, the peak lines of the horizontal and vertical components of the magnetic field of the Halbach-type guideway, respectively. Experimental results show that, in the temperature range from 77 to 73 K, the levitation forces decrease when increasing the YBCO bulk's round-trip movement times, whereas such influence is small at 68 K or lower temperatures. In addition, when the temperature of the bulk is held at 77 or 73 K, the levitation forces decrease when increasing the movement speeds from 1 to 6 mm/s. However, the influence of the movement speed on the levitation force is negligibly small at 63 K or lower temperatures. These conclusions are obtained in a large variation of the vertical component of the magnetic field. Once the variation of the vertical component of the magnetic field becomes roughly small, the influences of the bulk's round-trip movement times and speeds on the levitation force are very small at any temperature.