| Autor(en): |
Gerald Jungmayr, Wolfgang Amrhein, Walter Angelis, Siegfried Silber, Herbert Grabner und Dietmar Andessner |
| Journal: |
The 8th International Symposium on Magnetic Suspension Technology, Dresden / Deutschland |
| Jahr: |
2005 |
| Monat: |
September |
| Zusammenfassung: |
It is well known that the use of permanent magnetic journal bearings with axial stabilization is a very simple way to achieve magnetic levitation. While the radial stabilization is provided passively, the axial shaft position is controlled actively. This paper focuses on the whole design process for such a hybrid magnetic bearing. First of all, permanent magnetic journal bearings working with attractive and repulsive forces are compared. It will be shown that the radial stiffness to volume ratio of both bearing types are equivalent, if only the geometric parameters of magnet height and pole width are exchanged. This result is also true for multiple-ring structures. The radial stiffness and axial force of the permanent magnetic bearing is a function of the axial shaft position. The knowledge of these functions together with the axial start position define the necessary force to launch the shaft into the force-free equilibrium position and is the basis for the design of the active magnetic thrust bearing. Finally, an active magnet bearing using the Lorentz force is considered. Using the finite element method, the optimal geometry of the active magnetic bearing will be derived considering the ohmic and inductive drop. |
