. The Street railway journal . ed to the length of the line and its induction coefficient,also eventually upon the frequency. The induction coefficientand the frequency, or the value of <y L, exert also an influenceon the direction of the losses in the potential diagram, fromwhich the value of the resulting voltage at the feeding point(Esp) as well as that at Johannisthal (Ej) is greatly de-pendent. tained in the preceding year. As reliable speed recorders wereused in this years tests, the decrease in speed and the corre-sponding retardation could be accurately determined during theentire b
. The Street railway journal . ed to the length of the line and its induction coefficient,also eventually upon the frequency. The induction coefficientand the frequency, or the value of <y L, exert also an influenceon the direction of the losses in the potential diagram, fromwhich the value of the resulting voltage at the feeding point(Esp) as well as that at Johannisthal (Ej) is greatly de-pendent. tained in the preceding year. As reliable speed recorders wereused in this years tests, the decrease in speed and the corre-sponding retardation could be accurately determined during theentire braking period, from which the coefficient of frictionwas calculated. If we call, as in the preceding year, the Coefficient of friction f. Total pressure on the brake-shoes. D. Mass of the car ]\I. Rotating mass referred to wheel circumference. .. .R. Resistance of the car W■ Retardation p. 9/6 STREET RAILWAY JOURNAL. [Vol. XXVI. No. 23. then we have: p(M + R) — W (irades are not taken into D consideration in this equation,. From these values it is seen that the friction coefficient dur-ing the first part of the braking period decreases; but withfurther reduction in speed, rapidly increases. This agreesthroughout with the observations which Capt. Douglas Galtonpublished in the year 1878, according to which the friction co-efficient at a constant speed decreased with the continuation ofthe braking. But in the above brake tests the simultaneous de-crease in speed must be taken into consideration, as it resultsin an increase in the friction coefficient. On this account it isto be assumed that at the beginning of the braking period thedecrease in the friction coefficient with the time is greater than
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
