. Electric traction and transmission engineering . hus permits of the successive connectionof various contact studs thereon with stationary fingers,which, by means of suitable car wiring, are properly con-nected to the trolley or third rail, to the motors, andto the different rheostat terminals or compensator 47 shows a Westinghouse controller, for series-paralleloperation, with the cover removed. It has seven control-ling points in the series position and six in the parallelposition, and the motors are short-circuited during thetransition period. The direction of rotation of the mot
. Electric traction and transmission engineering . hus permits of the successive connectionof various contact studs thereon with stationary fingers,which, by means of suitable car wiring, are properly con-nected to the trolley or third rail, to the motors, andto the different rheostat terminals or compensator 47 shows a Westinghouse controller, for series-paralleloperation, with the cover removed. It has seven control-ling points in the series position and six in the parallelposition, and the motors are short-circuited during thetransition period. The direction of rotation of the motorsis changed by moving a reversing lever and thus actuatinga smaller cylinder which is beside the main cylin- 104 TRACTION AND TRANSMISSION. der of the controller and is provided with suitable contactpieces for effecting the necessary change in connections. In-terlocking devices are supplied, so that the reversing handlecannot be moved unless the controlling handle * is in sucha position that connection with the trolley or third rail is. Fig. 47. broken. The controlling handle also cannot be moved ifthe reversing handle is not properly set either for forwardor backward motion of the car. The reversing handle canbe removed from the controller only when in its neutralor ^^off position, to which it cannot be turned unless thecontrolling handle is also in its ^^off position, thus entirelydisconnecting the motor circuits from the trolley or third RAILWAY MOTOR CONTROL. 105 rail. Cut-out switches are provided, so that a defectivemotor or group of motors may be disconnected withoutinterfering with the operation of the remaining motor ormotors. As serious arcs are Hable to ensue upon breakinga circuit of 500 volts, the contact pieces and fingers areseparated from adjacent ones by strips of insulating mate-rials, which are usually fastened to the inside of a separatecover. Such arcs are effectively disrupted by the field ofan electromagnet, which is an essential part of contro
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Keywords: ., bookcentury1900, bookdecade1920, bookidelectrictrac, bookyear1920
