| 摘要 |
552,558. Motors. HITCHCOCK, S. I. July 9, 1941, No. 8665. [Class 35] A permanent magnet ot a permanent magnet motor has a "flux controller" consisting of a soft iron sleeve surrounding the pole pieces 1 of the magnet, or a plurality of soft iron bars 10 disposed on opposite sides of the pole pieces, and means, such as a cam 6 acting on spring loaded plungers 12, for periodically moving the flux controller lengthwise of the pole pieces into a position in which it lies flush with the end faces thereof, for the purpose of diverting the whole or a substantial proportion of the magnetic flux which would normally pass between the moving and stationary pole pieces when oppositely arranged, into the soft iron ports of the controller. In the form shown a cylindrical permanent magnet 3 has a four pole laminated pole piece 1 at each end, the whole rotating within a stator 4 having pole pieces 5. The angular position of cams 6, one at each end, are adjusted simultaneously by lever 7 and link 8. While a pole piece 1 is approaching or opposite a pole piece 5 the bars 10 are retracted, as shown in Fig. 3. As soon as the pole pieces are about to separate, the bars 10 rise flush with the surface of pole piece 1, as shown in Fig. 5, and weaken the attraction between the poles. Sufficient momentum is thus left to the rotor to enable it to get into the field of attraction of the next stator pole. If permanent magnets are employed in both stator and rotor, there will be two sets of flux controllers. Such motors will not be selfstarting or capable of perpetual motion. If either the stator or the rotor is an electromagnet, the motor can be started and maintained by intermittently energizing the windings ; the other member will then be a permanent magnet provided with a flux controller. The controllers may be moved electrically by windings energized separately or by a motor winding. To facilitate movement, a ball race or copper sheaths may be interposed between the flux controllers and the surfaces of the pole pieces. The Provisional Specification describes also an application to lifting magnets, the flux controller being movable by a Bowden wire or trip mechanism. The controller may be an insert in one of the poles. |
