. Electric trains . ph as ordinates and current in amperes £A9er^ de//Vr£recf^/ro/77 flfoCors CoA/e3 - 70% Fig. 72.—Showing Allocation of theEnergy Input of the Run Indi-cated in Fig. 66, with an Over-allEfficiency of Electrical Equipmentof 70 per cent. 142 ELECTRIC TRAINS 260220 1 50 200\tdO 1 40^ ^ 100 V ^ ^ ^ *\,l^0 \ X^ X^ % 50\ 20 \/00 / s ^-^ Q., ^^-^IJ ^ / 60604020 10 TFme 03eci i 0r er P7odor Fig. 74.—Characteristic (ml ph) Speed-Curve of the Train obtained from Fig, 73. POWER CURVES H3 as abscissae. This is done by taking pairs of readings on both curvesfor various times. With the dat
. Electric trains . ph as ordinates and current in amperes £A9er^ de//Vr£recf^/ro/77 flfoCors CoA/e3 - 70% Fig. 72.—Showing Allocation of theEnergy Input of the Run Indi-cated in Fig. 66, with an Over-allEfficiency of Electrical Equipmentof 70 per cent. 142 ELECTRIC TRAINS 260220 1 50 200\tdO 1 40^ ^ 100 V ^ ^ ^ *\,l^0 \ X^ X^ % 50\ 20 \/00 / s ^-^ Q., ^^-^IJ ^ / 60604020 10 TFme 03eci i 0r er P7odor Fig. 74.—Characteristic (ml ph) Speed-Curve of the Train obtained from Fig, 73. POWER CURVES H3 as abscissae. This is done by taking pairs of readings on both curvesfor various times. With the data that the car wheel diameter is1000 mm, and that the ratio of gearing is 2*47, we can now plotanother curve as in Fig. 75, with the speed of the motor in rpm asordinates and with the current in amperes as 40 dO /20 /60 200 2^ Current per Ahdor /n /Imperes. ^O Fig. 75.—Characteristic (rpm) Speed-Curve of the Motors. The values for these conversions are set forth in Table XLVIII.,together with the calculations for obtaining the successive curves. Table XLVIII.—Debivation of the Motor Speed-Curve. Time(seconds). Current inputto motor(amperes). Corresponding speed (ml ph). Speed(meters p min). Circumferenceof driving wheel(meters). Speed ofwheel(rpm). Speed of armature (rpm). 15 246 20-0 536 \ / 171 422 18 182 23-2 622 198 489 20 166 24-3 652 208 514 25 142 27-0 725 230 568 30 128 29-2 784 314 250 618 40 112 32-7 877 280 692 50 104 35-7 957 304 750 60 98-0 37-8 1014 323 798 70 96-5 39-5 1060 338 835 80 960 41-0 1100 1 350 865 144 ELECTRIC TRAINS Having obtained the speed-curve required, we can specify a motorof the rated hp required, 170 (see p. 133), and with a speed-curveapproximating to that of Fig. 75. Such a motor is suited to theconditions of the run indicated in Fig. 66. To
Size: 1866px × 1339px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1910
