. Electric railways; a treatise on the modern development of electric traction, including practical instruction in the latest approved methods of electric equipment and operation . r cutting in andout more or less resistance inthe shunt field coils of thegenerator so as to reduce orraise the voltage. There isa small switch for openingand closing the circuit throughthe shunt field coils. The main leads from thegenerator pass through twosingle-pole quick-break knife switches. The most recent practice is tohave the switches on the switchboard in only the positive and negativeleads from the genera
. Electric railways; a treatise on the modern development of electric traction, including practical instruction in the latest approved methods of electric equipment and operation . r cutting in andout more or less resistance inthe shunt field coils of thegenerator so as to reduce orraise the voltage. There isa small switch for openingand closing the circuit throughthe shunt field coils. The main leads from thegenerator pass through twosingle-pole quick-break knife switches. The most recent practice is tohave the switches on the switchboard in only the positive and negativeleads from the generator, leaving connection to the equalizer to bemade by a switch located on or near the generator. However, allthree leads may be taken to the switchboard, and a three-pole knifeswitch may be used instead of the positive and negative switchesspoken of. In Fig. 90 is given a simple diagram of the general relativeconnection of generators and feeders in a direct-current railwaypower station. It is seen that the generators are connected in parallelacross the positive and negative bus bar. There is a third bus bar—called an ec^ualizing bus—which connects in parallel the series. Fig. S9b. I-T-E Circuit Breaker. lus ELECTRIC RAILWAYS coils of all the fjenerator fields. Tlie object of this ecjualizer is toprevent the weakening of the series field of any one generator, so as toallow it to take current and to act as a motor instead of as a Up a Generator. Suppose that a new generator isto be started up and conneated to tlie bus bars in addition to othersalready in operation. The engine of that generator is first broughtup to speed. The switch controlling the shunt field circuit is thenclosed, causing current to flow through the shunt fields; and thegenerator begins to build up, its voltage gradually rising untilit approximates that upon the bus bars. Before the generator isthrown in parallel with the others by connecting it with the bus — Bus To ra/7s
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