Abstract
A superconducting magnetic bearing is a dynamic system, which undergoes vibrations at various frequencies during its operation. In this study, we investigated the free vibration frequency modes of a permanent magnet (PM) levitated over a high temperature superconductor (HTS) where the vibration was provided by the seismic activities of the earth. The amplitude of the vibration was less than 1 μm as measured by a vibrometer. A disk shaped PM was levitated over a melt-textured HTS YBCO (yttrium barium copper oxide). The experimental setup was adopted to do the fast Fourier transform analysis of the vibration characteristics of the levitated PM. A cross-coupling between the vibration frequency modes of vertical, lateral and angular is observed in all respective directions for any particular vibration frequency measurement. The results indicate that all the vibration modes are actually the combination of the pure vibration frequency modes. The theoretical predictions based on the frozen-image concept show that the ratio of the vertical to lateral stiffness should be higher than 2 in the dynamic case, which is observed experimentally.
| Original language | English |
|---|---|
| Pages (from-to) | 356-362 |
| Number of pages | 7 |
| Journal | Physica C: Superconductivity and its Applications |
| Volume | 390 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 15 Jul 2003 |
| Externally published | Yes |
Funding
This work partially supported by US Department of Energy and the Turkish Government. The author would like to thank J.R. Hull for providing experimental and advisory support.
| Funders | Funder number |
|---|---|
| Turkish Government | |
| US Department of Energy |