. The railroad and engineering journal . on a large machine is shown in fig. ii. Gramme replaced the single coil of wire, with its endsconnected to two brass segments on its axle, by a numberof separate coils wound on the circumference of a ring, asshown in fig. ii a. the ring being revolved also betweenthe poles of a magnet N and S, the ends of the coils be-ing connected to each other in such a way as to form acontinuous circuit all around the ring and also connectedto the various brass strips shown, which were securedseparately to the axle. As in the old Siemens machine,two brass
. The railroad and engineering journal . on a large machine is shown in fig. ii. Gramme replaced the single coil of wire, with its endsconnected to two brass segments on its axle, by a numberof separate coils wound on the circumference of a ring, asshown in fig. ii a. the ring being revolved also betweenthe poles of a magnet N and S, the ends of the coils be-ing connected to each other in such a way as to form acontinuous circuit all around the ring and also connectedto the various brass strips shown, which were securedseparately to the axle. As in the old Siemens machine,two brass brushes to which the ends of the outside wirewere attached pressed on these strips in succession, as- Vol. L^I. No. 12.] ENGINEERING JOURNAL. 552 the ring or armature revolved. A little consideration willshow that each one of the coils in a Gramme machine, inrotating, acts exactly like the single coil already described ;and. as the coils are connected together, all of the coilswhich are on the right side at any instant generate currents. in one direction, while all those on the other side are gen-erating currents in the opposite direction, because theright-hand coils are performing the first half of a revolu-tion, and the left-hand coils are performing the latter , if the currents were in the same direction in bothsides there would be one continuous current around thering, flowing down on one side and up on the other, butsince the currents are in opposite directions, they mustflow up or down on both sides, and, therefore, join forces Fig. I la.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
