Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. . g attracted and, as switch N is connected to it, bothswitch arms are simultaneously operated. Contacts 15 and 13 arethus opened, cutting the dynamotor entirely out of circuit. Currentnow flows from the trolley through the pivot of switch-arm N,through contact 14, direct to the control cir
Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc. . g attracted and, as switch N is connected to it, bothswitch arms are simultaneously operated. Contacts 15 and 13 arethus opened, cutting the dynamotor entirely out of circuit. Currentnow flows from the trolley through the pivot of switch-arm N,through contact 14, direct to the control circuits. The connection of wire 15 at the middle of the series field wind-ing is an important feature of the success of this scheme. W^hen thedynamotor starts up, the current in the series winding is effectivein producing a powerful torque as it strengthens the field. Whencurrent is drawn from the middle of the series winding to supply 174 ELECTRIC RAILWAYS 79 the control circuits, it flows partly through armature A and partlythrough A. These two components of the current flow in oppositedirections in the series winding and thus neutralize each other. Theseries winding has, therefore, no effect on the operation of the machinewhen it is running as a generator, but is effective only when it isa motor. 175. ELECTRIC RAILWAYS PART II BRAKES AND BRAKING The standard device for bringing cars to rest is the brake-shoealready illustrated under the subject of truck details. The brake-head and shoe is carried by a link or hanger as shown in Fig. 80,which supports the weight but leaves the head free to move in thedirection of the wheel radius. The head and shoe are pushed orpulled by a system of levers, rods, and chains, thus, by means offriction, producing a retarding force on the wheel rim. The brake-heads may be hung either between the wheels (inside hung) oroutside the wheels (outside hung).
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Keywords: ., bookauthoramericantechnicalsoci, bookcentury1900, bookdecade1910
