Sync. motor with axially movable permanent magnet rotor - has two sets of rotor poles and magnetic ring biassing rotor in required direction

摘要

The synchronous motor has a permanent magnet rotor which can be moved axially along its axis. It has a first set of poles (28') arranged around and on the rotor (14). A second set of poles (28") is arranged between the poles of the first set. The poles of the second set are shorter than those of the first set. A magnetically active element (60) is set off in the direction in which the rotor is to be axially biased. It is operatively connected with the rotor. This element may be formed as a ring held by a hub of the rotor.