. The Street railway journal . ONTROLLER The provision made in the master controller, of both systems ofcontrol, for opening the main circuit and applying the air brakeswhenever the motorman releases the controller handle, is con-sidered a valuable safety feature, and its application is so simpleas to well warrant its use. The master controller on both systemsis very small and compact, as it handles only the small currents ofthe operating wires. In the Sprague-General Electric system thecontrol circuits require not over 2^2 amps, at 600 volts, with two125-hp motors, and in the Westinghouse sys
. The Street railway journal . ONTROLLER The provision made in the master controller, of both systems ofcontrol, for opening the main circuit and applying the air brakeswhenever the motorman releases the controller handle, is con-sidered a valuable safety feature, and its application is so simpleas to well warrant its use. The master controller on both systemsis very small and compact, as it handles only the small currents ofthe operating wires. In the Sprague-General Electric system thecontrol circuits require not over 2^2 amps, at 600 volts, with two125-hp motors, and in the Westinghouse system not over 10 amps,at 14 volts for a ten-car train. 568 STREET RAILWAY JOURNAL. [Vol. XXVI. No. 14. LINE RELAY In both systems a potential or line relay is provided which opensthe main circuit whenever the supply of current from the line isinterrupted. When the current is again restored to the line thecontactors are closed through successive resistance steps beforereturning to their former positions. This device obviates the. GROUP OF SPRAGUE-GENERAL ELECTRIC CONTACTORS IN CASE WITH COVER OPEN shock which would otherwise occur in passing over road crossingsor turnouts where the continuity of the third rail is broken. BUS LINE In connection with multiple systems of control, it is often ad-visable to install a bus line cable throughout the train connectingthe several contact shoes, so that in case the shoes of one car arenot in contact with the third rail, the motors of this car mayreceive current through the bus line from the other cars. Thebus line greatly facilitates operation where it is necessary to inter-rupt the continuity of the third rail at street crossings or yards,and at such points a continuous supply of current for motors andfor car lighting is thereby maintained. The bus line also serves toeliminate motor flash-overs, which sometimes occur when the carsare running at high speed, and the supply of current is suddenlyinterrupted and restored, as is thecase when the
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
