. A textbook on electric lighting and railways. International correspondence schools, Scranton, Pa. v. 1-3, 5 . that the drop shall not exceed100 volts even if all the cars are concentrated at one end ofthe road ? Ans. 149,728 cir. mils. (5) What are some of the results of operating street carson too low a voltage ? (6) {a) Why must not the tread of a car wheel be grounddown too much ? {b) How can one tell whether or not a fiatcan be advantageously removed by grinding the tread of awheel ? (7) What is meant by electrolysis in electric-railwaywork ? §23 ELECTRIC RAILWAYS. (8) What points on und
. A textbook on electric lighting and railways. International correspondence schools, Scranton, Pa. v. 1-3, 5 . that the drop shall not exceed100 volts even if all the cars are concentrated at one end ofthe road ? Ans. 149,728 cir. mils. (5) What are some of the results of operating street carson too low a voltage ? (6) {a) Why must not the tread of a car wheel be grounddown too much ? {b) How can one tell whether or not a fiatcan be advantageously removed by grinding the tread of awheel ? (7) What is meant by electrolysis in electric-railwaywork ? §23 ELECTRIC RAILWAYS. (8) What points on underground-cable sheaths, waterpipes, etc. are Hable to injury by electrolysis ? (9) What are the advantages and disadvantages ofoperating cars on the three-wire system ? (10) Fig. Ill shows the layout of a single-track roadoperating eight cars, each car requiring an average cur-rent of 25 amperes. The road is divided into three sec-tions by means of line breakers, each section being providedwith a No. 00 main having a cross-section of approximately133,000 circular mils and a resistance of about .08 ohm per. Tro/feyiVlreNoOO 1,000 feet, including joints, etc. The mains are fed by thefeeders i, 2, and S. Feeders running parallel to those forthe overhead system and of the same size are to be usedfor connecting the track circuit to the power station. Thetrolley wire is No. 00, having a resistance of about .08 ohmper 1,000 feet and a cross-sectional area of approximately 4 . ELECTRIC RAILWAYS. §33 133,000 circular mils. Calculate the size of feeders requiredin order that the drop at any one of the cars, if they areall in the positions shown by the small, round dots, shallnot exceed 50 volts. Wherever convenient, formula 3 isto be used in the computations. ! Feeder 1, 75,004 cir. 2, 362,923 cir. 3, 370,400 cir. mils. (11) (a) Calculate the drop at the car at a in Fig. Ill,assuming that No. 00 wire, whether trolley wire or main,has a resistance of .08 ohm per
Size: 1752px × 1426px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectelectri, bookyear1901
