. Electric railway gazette . FIG. , and since in the street car motor this Is. afirst requisite, we never sea the ring armature em-ployed. On the other hand, in machines of greatsize, such as street railway generators. It is morefrequently employed than the drum armature,chiefly for structural reasons. CONSEQUENT POLES AND MULTIPOLAR FIELDMAGNETS. Heretofore in considering magnets we havedealt only with those of a straight bar, or horse-. FIG. shape, having two poles, or the closed ironring, with the closed magnetic circuit having nopoles at all. Before proceeding further it ma
. Electric railway gazette . FIG. , and since in the street car motor this Is. afirst requisite, we never sea the ring armature em-ployed. On the other hand, in machines of greatsize, such as street railway generators. It is morefrequently employed than the drum armature,chiefly for structural reasons. CONSEQUENT POLES AND MULTIPOLAR FIELDMAGNETS. Heretofore in considering magnets we havedealt only with those of a straight bar, or horse-. FIG. shape, having two poles, or the closed ironring, with the closed magnetic circuit having nopoles at all. Before proceeding further it may bewell to speak of two other forms frequently usedboth In dynamos and motors. Suppose we have a closed magnetic circuit as In Fig 43, and placeupon it on one side a coll with a current passingaround it so as to make Its upper portion a northpole and its lower portion a south pole. If nothingmore were done, the lines of force would flowaround—part of them through the armature andperhaps a greater portion would flow aroundthrough the other leg on the right. All theselatter would be lost, so farasour armature Is con-cerned. But if we place a second coil so as tomake the upper part of the magnet a north polealso, It win drive these lines back and send addi-tional lines of its own in the same dire,clion. Infact the effect of the two coils working in oppo-
Size: 1610px × 1553px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidelectricrail, bookyear1895
