. Electric traction and transmission engineering . in a for the master control is taken from the line, orfrom a storage battery, through whichever master controllerthe motorman operates. Since this current is used solelyfor energizing the operating coils of the motor contactors,its value is comparatively small, usually not amperes for each car equipment. As the operatingcoils of each motor controller are connected to the wiresof the control cable, any master controller on the trainwill simultaneously operate corresponding contactors on io6 TRACTION AND TRANSMISSION.
. Electric traction and transmission engineering . in a for the master control is taken from the line, orfrom a storage battery, through whichever master controllerthe motorman operates. Since this current is used solelyfor energizing the operating coils of the motor contactors,its value is comparatively small, usually not amperes for each car equipment. As the operatingcoils of each motor controller are connected to the wiresof the control cable, any master controller on the trainwill simultaneously operate corresponding contactors on io6 TRACTION AND TRANSMISSION. all the motor cars and thus establish similar motor con-nections on them. To avoid accidents which may occurthrough the physical disability of a motorman, the operat-ing handle of the master controller is sometimes providedwith a button which must be held down in order to keepthe auxiliary control circuit closed. In some cases the con-nections are so arranged that releasing this button appliesthe air brakes as well as opens the control Fig. 48. The essential features of the multiple-unit system ofcontrol as applied to direct-current equipments are illus-trated in Fig. 48, which shows the principal motor andcontrol circuits for one motor car. For clearness the re-verser is omitted, as are also the circuits necessary for itscontrol. Assuming therefore that the reverser is properlyset, the subsequent operation of the control system duringinitial acceleration is as follows: turning one of the mastercontrollers to the first notch results in the closing of contac- RAILWAY MOTOR CONTROL. 107 tors a, b, and h, due to current received from train wires r,2, and 8, thus establishing connection with the line andplacing the two motors and a protecting resistance inseries. Turning the master-controller handle successively tonotches 2, 3, and 4 closes contactors c, d, and e, respectively,thereby progressively reducing the resistance by placingadditional resistance units in parallel
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Keywords: ., boo, bookauthorsheldonsamuel1862, bookcentury1900, bookdecade1910
