. The Berlin-Zossen electric railway tests of 1903. A report of the test runs made on the Berlin-Zossen railroad in the months of September to November, 1903 . heyear 1902; , by a long series of coasting runs, which this time were begunwith a far higher initial speed. For these tests the improvement on the speedindicators, as mentioned on pages 17 and 19, proved to be very useful. Themeasurement of the speed was greatly facilitated by the use of the new clockworkcontact device, which made a record on the drum at intervals of two rail contacts also made it possible to determine
. The Berlin-Zossen electric railway tests of 1903. A report of the test runs made on the Berlin-Zossen railroad in the months of September to November, 1903 . heyear 1902; , by a long series of coasting runs, which this time were begunwith a far higher initial speed. For these tests the improvement on the speedindicators, as mentioned on pages 17 and 19, proved to be very useful. Themeasurement of the speed was greatly facilitated by the use of the new clockworkcontact device, which made a record on the drum at intervals of two rail contacts also made it possible to determine for each test run the ratiobetween the revolutions of the wheels and the actual distance run through. Finally, the greatest accuracy was attained in working up the records onthe strips of paper by using a transversal glass rule with an etched scale espe-cially made for this purpose, together with a very strong magnifying-glass. Thespeed curves obtained in this manner had to be reduced to the horizontal inorder to eliminate down grades. This was done in the following manner: InFigure 17 let abed be the speed curve as found by the records, the track being. y Fig. 17. horizontal between a and b, and between c and d, and having a down grade of h — between b and c. If Q is the weight of the car, then it is acted upon by the Qhforce —, which would produce an acceleration p if the car was on a horizontal Qh Qkstretch. It is therefore — = p-^, and wherein fe is a factor which takes into I g hg Yx-Y^!consideration the moving masses. From this equation we find -^=p = —, ;—. 32 BERLIN-ZOSSEN ELECTRIC RAILWAY TESTS. From this we can calculate Vi — Vi =innii, and construct the line bm, c, d, whichrepresents the speed curve, if the track were horizontal between h and c. Fromthese corrected speed curves the retardation and the retarding force were found;, the total resistance of the car at different speeds. On Plates XIV, XlVfl andXV these calculated values are plotted in, for
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectelectri, bookyear1905
