Design and Validation of Switchable Tracks for Superconducting Levitation Systems

Levitation force measurement on a switchable track for superconducting levitation systems

“…The YBCO-double bulk was positioned inside a brass vessel and cooled with liquid nitrogen. The investigations were performed on a 150 mm long PMT segment of the SupraTrans system and on the switchable demonstration track segment described in detail previously [15]. Figure 3 shows this CST demonstration segment in the measurement setup.…”

“…Levitation force measurements in FC mode used vertical movement from z=40 mm down to the minimal height (3 mm or 5 mm, respectively) and back to 40 mm. The different minimum heights originates from differences in the generated magnetic field profile measured above the CST in comparison to the PMT [15,16]. Based on these studies it was assumed that the CST will require a smaller levitation height to generate the same levitation force as the PMT.…”

“…The specific track design not only influences the flux density but also the gradient of the magnetic flux density. In particular, the CST exhibits a lower gradient and a lower absolute magnetic flux density at the position of the superconductor if compared with the PMT [15] due to its design. The increased track height of the CST leads to an increased flux ratio leaving the track at the side of the flux collector instead at the top of the pole and therefore reduces the absolute flux density inside the superconductor working area.…”

“…However, suitable copper-based coils arranged together with an iron yoke or another flux collector require too much space to implement them effectively in a full-scale levitation system [12][13][14]. Instead, a combination of permanent magnets, flux collectors and a superconducting coil was chosen in a so-called combined switchable track (CST) to control the magnetic flux density above the track [15]. The new design was derived from the current PMT of the SupraTrans test facility (figure 1(a)).…”

“…To do so, the PMT was extended by longer flux collectors, an additional coil made from YBCO coated conductors beneath the permanent magnets and an iron yoke at the bottom of the track (figure 1(b)). The detailed design of the switchable track is described in more detail in [15].…”