. Electric railway journal . September 30, 1916 ] ELECTRIC RAILWAY JOURNAL the motors for emergency braking in case of fail-ure of the air brakes. The automatic acceleration feature of this con-trol is particularly interesting as the action of thecurrent-limiting relay is modified by the currentpassing through an auxiliary winding of the relay,in such a way as to provide for the same rate ofacceleration for all loads. The amount of currentpassing through this auxiliary winding is con-trolled by a switch operated in connection withthe variable-load brake mechanism. The adjust-ment of this mecha
. Electric railway journal . September 30, 1916 ] ELECTRIC RAILWAY JOURNAL the motors for emergency braking in case of fail-ure of the air brakes. The automatic acceleration feature of this con-trol is particularly interesting as the action of thecurrent-limiting relay is modified by the currentpassing through an auxiliary winding of the relay,in such a way as to provide for the same rate ofacceleration for all loads. The amount of currentpassing through this auxiliary winding is con-trolled by a switch operated in connection withthe variable-load brake mechanism. The adjust-ment of this mechanism corresponds directly to thedeflection of the bolster springs under for the control circuit is obtained from a34-volt storage battery which also furnishes energyfor emergency car light, signal lights, door inter-locks and other special circuits. This control isdesigned for use with the larger motors, thoseon the New York Municipal cars being rated at160 hp. on 600 volts. <3v to o -t c s;o ic £ 1 c1 is LP,. ► >■ Hi T Motor Grouping for Non-Rheostatic Control The PC control equipment, recently placed onthe market by the General Electric Company is an-other indirect system designed to secure maximumreliability with minimum weight. It is being con-structed in a wide range of sizes, and is expectedto supersede the older forms of General Electricindirect control. The important parts of this sys-tem are a motor controller and a master motor controller consists of a group of switchesor contactor units (used for effecting the seriesand parallel groupings of the motors and in cuttingout resistance), together with a reverser, a circuit-breaker and overload, potential and current-limit-ing relays, all of these being assembled in a singlecase. The contactors are closed mechanically bymeans of cams mounted on a shaft which is re-volved by a rack and pinion. The rack is operatedby two air cylinders, whose valves are electricallycontrolled by the maste
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