| 摘要 |
1277876 Core construction JOSEPH LUCAS (INDUSTRIES) Ltd 23 July 1969 [16 Aug 1968] 39324/68 Heading H2A In a D.C. dynamo-electric machine comprising a yoke, a plurality of poles and a wound armature, the flux path between the yoke and that part of each pole face beneath which armature reaction tends to reduce the flux has a higher reluctance than the flux path between the yoke and the remainder of the pale face. In one embodiment (Fig. 2) each pole comprises a low-reluctance steel part 11 bolted to the yoke and a ferrite magnet 12 held alongside the part 11 by spring 14. In a modification (Fig. 6, not shown) a bent-in portion of the yoke replaces steel part 11. In other embodiments each pole comprises a ferrite block of varying thickness (19, Fig. 4) or two separate blocks of different thickness, as 15, 17, Fig. 3. In Fig. 3, each block carries a steel pole piece 16, 18. |
