The electric railway

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McGraw-Hill, 1915 - Electric railroads - 390 pages
 

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Page 142 - ... when operated on stand test with motor covers and cooling system, if any, arranged as in service. Inasmuch as the same motor may be operated under different conditions as regards ventilation, it will be necessary in each case to define the system of ventilation which is used. In case motors are cooled by external blowers, the volume of air on which the rating is based shall be given.
Page ii - Electrical World The Engineering andMining Journal Engineering Record Engineering News Railway...
Page 141 - ... which causes a rise of temperature above the surrounding air, by thermometer, not exceeding 90 C. at the commutator, and 75 C. at any other normally accessible part after...
Page 141 - The nominal rating of a railway motor shall be the mechanical output at the car or locomotive axle, measured in kilowatts, which causes a rise of temperature above the surrounding air, by thermometer, not exceeding 90 "C. at the commutator, and 75 C. at any other normally accessible part after one hour's continuous run at its rated voltage (and frequency in the case of an alternating-current motor) on a stand with the motor covers arranged to secure maximum ventilation without external blower.
Page 148 - ... as the energy of a moving body is proportional to the square of its velocity, the energy absorbed by the water will increase in even more rapid ratio.
Page 134 - Standard deviation is a measure of dispersion in a frequency distribution equal to the square root of the mean of the squares of the deviations from the arithmetic mean of the distribution.
Page 280 - The equation of the ellipse is given by 2 2 a~ b~ where x and y are the coordinates of any point on the ellipse and a and b are the values of the minor and major semi-axes respectively.
Page 15 - ... energy as part of their thermal energy. The view therefore is plausible that the emission and absorption of radiant energy in band spectra represent changes in this rotational energy. If molecules were really rigid bodies, the application of Bohr's principles to the suggestion would be simple. If / is the moment of inertia of the body about its axis of rotation, to the angular velocity of rotation, the energy of rotation is given by W =\Ia?
Page 31 - Velocities can be treated as vectors and as such, can be added and subtracted by graphical methods. More specifically velocity is the rate of change of distance with respect to time. It is most often stated in units of miles per hour, or feet per second. The average velocity is equal to total distance divided by total time. Velocity may be constant or may increase or decrease with respect to time. VELOCITY OF SOUND IN AIR: 1,090 feet per second.
Page 104 - One oond point. One motor is completely short circuited on the third notch, after which it is connected to the line through resistance. On the next transition point, a second motor is reversed, thus placing it in series with the other and the resistance. On the fourth notch, the re-sistance is cut out, leaving the motors in series-parallel connection. The next transition point is similar to the other transition connections, except that but 3 motors are in circuit. The fifth and sixth positions really...

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