. Electric railway journal . exciter, which is so connectedas to super-excite the traction motor fields. By prop-erly proportioning the design of the exciter for itsservice, the stable characteristic of the series motor isinherent in the braking connection as in the motor con-nection. Since the generative function is a reversalof the motor function, the traction motors provide inregeneration that, with an increase in speed, there is anautomatic increase in braking effort, and with a de-crease in speed there is an automatic decrease in brak-ing effort, a definite torque corresponding always toe
. Electric railway journal . exciter, which is so connectedas to super-excite the traction motor fields. By prop-erly proportioning the design of the exciter for itsservice, the stable characteristic of the series motor isinherent in the braking connection as in the motor con-nection. Since the generative function is a reversalof the motor function, the traction motors provide inregeneration that, with an increase in speed, there is anautomatic increase in braking effort, and with a de-crease in speed there is an automatic decrease in brak-ing effort, a definite torque corresponding always toeach particular speed and voltage. The fact that thisstable characteristic is closely maintained during regen-erative braking is one of the greatest contributing ele-ments to the success of electric braking in this service,because it permits operation down grades at constantspeed with but little regulation by the motorman, exceptas changes in grade or curves produce large variationsin the intensity of braking power C, M. & ST. P. LOCOMOTIVES—INTERIOR VIEW OF MOTORMANSCAB SHOWING CONTROLLER AND ELECTRIC-BRAKING HANDLESAND OPERATING GAGE BOARD So far as the motorman is concerned the operation issimple. When motoring he varies his tractive effort bychanging the resistance in series with his tractionmotors, thereby limiting the amount of power to beexpended in the motors. When braking he merelychanges the resistance in the shunt field of his exciter,thereby regulating the increment of voltage above theline, the returned power reacting as a braking effort. The equipment used in producing this result includesa small controller inverted upon the large master con-troller, the handle for the former being used for varyingthe intensity of the retarding torque, which may beaccomplished when the motors are running either in fullseries or full parallel. An illuminated ammeter and gagepanel is located directly in front of the motorman. Thisis provided with a center-zero ammeter fo
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