. Electrical world. , or 55 amp. at 400 volts carriedcontinuously during a shop test, the rise in temperature of the motorwindings, as measured by thermometer, after ten or twelve hours,or after a constant temperature has been reached, will not exceed75° C. With equivalent lead under a moving car the temperaturerise should not exceed 55° C. Heavier loads may be carried forshorter periods, as indicated by the time temperature curve. If, forexample, the motor has been working at a load of 60 amp. at 300volts, and has reached a temperature of 75° C, it may then carrya load of yz amp. at 300 volts
. Electrical world. , or 55 amp. at 400 volts carriedcontinuously during a shop test, the rise in temperature of the motorwindings, as measured by thermometer, after ten or twelve hours,or after a constant temperature has been reached, will not exceed75° C. With equivalent lead under a moving car the temperaturerise should not exceed 55° C. Heavier loads may be carried forshorter periods, as indicated by the time temperature curve. If, forexample, the motor has been working at a load of 60 amp. at 300volts, and has reached a temperature of 75° C, it may then carrya load of yz amp. at 300 volts for one and one-half hours, with addi-tional rise in temperature not exceeding 20° C. Speed, tractive effort,efficiency and power developed are also indicated for different gearratios and under conditions ranging from currents of 30 to 240 the normal potential of 500 volts. The frame of the motor is made of cast steel divided horizontallyin two parts, forming a field which i; wholly iron chd. and approx-. FIG. 2.—MOTOR .\.\D PINION. imately cylindrical in shape. The design is such that when mountedon the truck the holding bolts may be withdrawn and the upperfield lifted off. To this end the suspension lugs and projection forthe support of the gear case are cast with the lower field. A largeopening with a spring-locked cover permits access to the commu-tator and brushes. Hand-holes are provided in convenient locationsabout the motor frame. The four pole pieces are built up of softsteel punchings riveted together between end plates of wroughtiron and are held to the motor frame by bolts. The poles projectradially inward at angles of 45° w:ith the horizontal. The boltsholding the pole pieces in place do not penetrate the pole face, butterminate in heavy rivets inside the pole made for this purpose. Asmooth and unbroken pole face is thus presented to the poles are made with projecting tips, which properly distribute the magnetic field, and also serve to
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
