| 摘要 |
<p>Apparatus comprises a cylindrical housing having two portions (6, 7) each defining a respective semi- cylindrical internal surface, one of the surfaces being magnetised to have one polarity and the other of the surfaces being magnetised to have an opposite polarity. A cylindrical rotor (1) made of non-magnetic material is mounted for rotation in the housing, the rotor having peripheral slots (2) extending outwardly of the axis of rotation of the rotor and slideably receiving therein magnetic pieces (3). The radial clearance gap (12) between the rotor (1) and the housing portion (7) is greater than that between the rotor and the portion (6). The magnetic pieces (3) are attracted by the internal surface of housing portion (7) and are repelled by the internal surface of housing portion (6). Thus, if the rotor is given an initial rotation, the magnetic pieces move inwardly and outwardly in their respective slots as the rotor rotates. <IMAGE></p> |
