. The Street railway journal . It consists of ahigh-range ammeter connected in series with the power line ofthe train. The range of this instrument is of sufficient magni-tude to permit of a deflection without banking, equivalent tothe maximum current imput of the motors. Mounted rigidly sudden variations of speed, will indicate when a straight lineinclined to the axis that the speed is constant, and will serveas a check when plotting the speed-time curve. It is customary when investigating the results of tests toplot all of the variables upon the same sheet with time as theabscissa, so that a
. The Street railway journal . It consists of ahigh-range ammeter connected in series with the power line ofthe train. The range of this instrument is of sufficient magni-tude to permit of a deflection without banking, equivalent tothe maximum current imput of the motors. Mounted rigidly sudden variations of speed, will indicate when a straight lineinclined to the axis that the speed is constant, and will serveas a check when plotting the speed-time curve. It is customary when investigating the results of tests toplot all of the variables upon the same sheet with time as theabscissa, so that at any time interval the distance covered,the speed, the power consumption, the current input, the volt-age and the acceleration may be readily compared. The speedcurve (Fig. 4) was obtained by drawing tangents to the dis-tance curve. This particular test was selected because it contained bothgrades and a curve. The car left station A upon a curve and aslight up-grade. When emerging from the curve the grade +2. 200 r- +1. 100. P 2000 lliOO -:o 50 Time in Seconds FIG. 4.—TEST DIAGRAM PLOTTED FROM RECORDS MADE BY RECORDER no 100 Street ; upon a spindle in front of the ammeter is an arm with a pointeron one extremity and a handle on the other end. This handlecan be moved by the operator with a little practice so that thepointer may accurately follow the variations of the ammeterneedle. By means of a fine wire passed several times around apulley mounted upon the fulcrum of the handle, the motionof the pointer may be transmitted to a sliding rest upon whichis situated the current-recording pencil. The wire is kept tautby passing it around two additional pulleys in a similar mannerto that of an endless belt (see Fig. 2). The instruments, asnow designed by Mr. Keiley, have an additional attachmentsimilar in every respect to the current-recording device, torecord voltage (see Fig. 3) requiring the services of an ad-ditional operator. In the tests made by the writer, voltmeterr
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
