. The Street railway journal . f the resistance step by thecontactor causes an increased current to flow through themotor circuit and through the heavy coil of the throttle relay,which is sufficient to hold the relay plunger in its raised posi-tion, and so keeps the accelerating circuit open until the motors October i, 1904.] STREET RAILWAY JOURNAL. by speeding up cause the current to diminish enough to allowthe relay plunger to drop. Circuit is then established throughthe contactors shunting the second resistance step (the firstcontactor having shifted this circuit also), and these contac-tor
. The Street railway journal . f the resistance step by thecontactor causes an increased current to flow through themotor circuit and through the heavy coil of the throttle relay,which is sufficient to hold the relay plunger in its raised posi-tion, and so keeps the accelerating circuit open until the motors October i, 1904.] STREET RAILWAY JOURNAL. by speeding up cause the current to diminish enough to allowthe relay plunger to drop. Circuit is then established throughthe contactors shunting the second resistance step (the firstcontactor having shifted this circuit also), and these contac-tors are energized and the relay again lifted and held up by theincreased current, and so on until all the resistance is cut out. When the master controller is moved to the third position,the parallel circuit is established, and the bridge contactor andthen the parallel contactors closed and the motors connectedin the multiple arrangement. When the master controller ismoved to its fourth or full-on position, the resistance is cut. FIG. 6— MASTER CONTROLLER SWITCHES out step by step as in series. These same successive actionsare produced if the master controller is thrown to the full-onposition directly, as the interlocking contacts prevent an ad-vance circuit being established before the proper preliminaryaction has taken place. If at any point during the acceleration, the master controlleris moved to its lap position, the existing positions of thecontactors are maintained, but the further progression is ar-rested so that the motorman can limit the acceleration to asslow a rate as desired, but he cannot exceed the predeterminedrate for which the relay is adjusted. The sixth wire in the train line above referred to, providingan emergency cut-off, is connected to a switch in the motor-mans cab and to trip magnets on the t«p of the cut-out switches(Fig. 7, lower part) provided on each car of the train. All ofthe control circuits for each car pass through its individualcut-out swit
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
