| 摘要 |
<p>339,941. Blum, C. R. Sept. 9, 1929. Motors with unwound iron armatures.-The stator of the secondary machine of a synchronous system which comprises two coaxial pole rings arranged so that adjacent poles in each ring as well as in the direction of the axis are of opposite polarity, the exciting current being allowed to flow for a certain period in one group after the energization of the next group. A plurality of contacting devices may be arranged to vary the ratio of the speeds of the two machine. The twenty-four poles of the driven machine 2, Fig. 1, twelve of which are shown, are arranged in three groups a<1>, b<1>, c<1> each consisting of eight poles, the groups being energized successively from mains 15, 16, either through a distributor 4 mounted on the shaft of the machine 1, or a distributor 57 mounted on a shaft driven by the hand-crank 56, selection being made by the switch 55. The distributors 4, 57 have twelve segments arranged in three groups a, b, c and the brushes 14, 58, in passing from one segment to the next connect to both for a short period, and give the armature 19 an intermediate position between the groups of poles. The armature 19 comprises four pole-shoes 24 of very soft iron carried on non-magnetic shanks 25 mounted on a shaft 20. Specification 125,454 is referred to.</p> |
