Lateral restorable characteristics of the high-Tc superconducting maglev vehicle above the permanent magnet guideway

The lateral restorable characteristics of a translational symmetry high-Tc superconducting maglev system are investigated by measuring its resonant frequency (fRF) after a lateral displacement. The difference between whether this lateral displacement is restorable, meaning elastic or inelastic, is determined by whether or not the maglev body returns to its original position after a lateral displacement. The maximum restorable lateral displacement (δMRLD) is determined by the sudden change of the fRF vs. the maximum lateral displacement (δMLD) curve. The fRF of the high-Tc superconducting maglev system with different field-cooling height (FCH) and working height (WH) was obtained from the frequency domain vibration curve which was measured by a vibration measurement system. The results showed that, the δMRLD was reduced when the WH was decreased. The maximum restorable guidance force (FMRGF) was found to not always increase with the lowering of the WH for the same FCH. The lateral restorable stiffness (kLRS) was always enhanced with the decrease of the WH. The decrease of the δMRLD with the WH is interpreted by the fact that, the tangential field component (ΔH) across the surface of the high-Tc superconductor (HTSC) is easier to exceed the Jcλ value (Jc is the critical current density and λ is the London penetration depth) when the WH is lowered, and this makes the trapped flux lines become more susceptible in escaping its pinning sites.