. Electric traction for railway trains; a book for students, electrical and mechanical engineers, superintendents of motive power and others .. . Fig. 169.—Typical Curve on Relation of Speed to Northern Railway eight-car passenger train number 1, The Oriental Limited. Curve by Schalter speed recorder. above efficiency 5 to 20 per cent., depending upon the distance and loads,making the total efficiency 50 to 65 per cent. When high-voltage con-tact lines are used, and substations are omitted, the efficiency variesfrom 65 to 85 per cent. 1000 50 800 40 •a coo ^30 400 30 200 10 «< 3^
. Electric traction for railway trains; a book for students, electrical and mechanical engineers, superintendents of motive power and others .. . Fig. 169.—Typical Curve on Relation of Speed to Northern Railway eight-car passenger train number 1, The Oriental Limited. Curve by Schalter speed recorder. above efficiency 5 to 20 per cent., depending upon the distance and loads,making the total efficiency 50 to 65 per cent. When high-voltage con-tact lines are used, and substations are omitted, the efficiency variesfrom 65 to 85 per cent. 1000 50 800 40 •a coo ^30 400 30 200 10 «< 3^0 TYPICAL CURVES SHOWING RHEOSTAT LOSSES S«^ I 6 CAR TRAIN 4 MOTOR GARS-145TONS ~±p RATE MILES PER SEC PZA STATION STOP 0 10 20 30 40 50 60 70 SecondsFig. 170.—Power, Speed, and Time Curves Obtained by Putnam on the Manhattan Elevated Railway. POWER CURVES. To illustrate the change of speed or tractive effort with referenceto time or to distance, power curves are used. See Fig. 169. Illustrativecurves, in simplest form, from Putnams paper on Power Economy onManhattan Elevated Railroad, to A. I. E. E., July, 1910, are also shown. 422 ELECTRIC TRACTION FOR RAILWAY TRAINS WATT-HOURS PER TON-MILE. The energy which is required for trains is generally expressed inwatt-hours per ton-naile. The energy required is proportional to, anddependent on, the tractive effort required per ton to overcome friction,inertia, and grades. The energy required per ton-mile does not dependon the speed. It is not a function of the speed but of the speed, however, increases the friction or tractive effort. The average numerical value of the tractive resistance, or the valuesof the train resistance for different
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Keywords: ., bookcentury1900, bookdecade1910, bookidelec, booksubjectrailroads
