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Journal of electricity, power, and gas . hold-ing wire, in the control circuit. The relay is ener-gized whenever the pantograph is on the trolley andopens the interlocks on the control wires to the com-mutating switch, closing the interlocks on the No. 2wire. As soon as a dead section is reached by the panto-graph the relay drops out, the interlocks on the commu-tating switch control wires make contact, and the com-mutating switches can then be thrown automaticallyas each car passes the change over or dead sectionfrom 600 to 1500 or vice versa. This is brought about 402 JOURNAL OF ELECTRICITY,
Journal of electricity, power, and gas . hold-ing wire, in the control circuit. The relay is ener-gized whenever the pantograph is on the trolley andopens the interlocks on the control wires to the com-mutating switch, closing the interlocks on the No. 2wire. As soon as a dead section is reached by the panto-graph the relay drops out, the interlocks on the commu-tating switch control wires make contact, and the com-mutating switches can then be thrown automaticallyas each car passes the change over or dead sectionfrom 600 to 1500 or vice versa. This is brought about 402 JOURNAL OF ELECTRICITY, POWER AND GAS tVol. XXXII—No. 19 by the motorman throwing the valve switch abovementioned to the desired position on the head car,which throws the commutating switch on the firstcar by air direct; commutating switches on the fol-lowing cars then throw electro pneumatically. It isnecessary to hold the valve switch handle in positionuntil all cars are across. It is necessary when throw-ing the switch on the leading car or single car to. Combination Passenger and Baggage Car. have the controller in the off position, as the practiceis to change over head car just before getting on thedead section. It is not practicable to change over to1500 volt position on 600 volt trolley as the dynamotorsthat furnish light, control current and air will notgenerate enough voltage to pick up contactors in thiscombination. The dynamotor has a double wound armature,the 1500 volt winding motoring the compressor, andgenerating on the 600 volt end current for lightingand control. On 600 volt the 600 volt end motorsthe compressor and the 1500 volt end remains is accomplished by special connections andchanges made when the commutating switch isthrown. The dynamotor has a permanent resistanceof 18 ohms between it and the trolley connection inthe 1500 volt position. The air compressor is operated by means of aclutch which is engaged and disengaged by air pres-sure. The air pressure is gover
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Keywords: ., bookauth, bookcentury1800, bookdecade1890, booksubjectelectricity