THE OPERATION OF THE DYNAMO AS A MOTOR. 125 



wire and the rail without 'any rheostat in its circuit. Of course 

 if two of these motors are used in parallel without any resistance 

 connected in series with them, the total tractive effort will be 

 twice as great at a given speed as that shown in Fig. 94. 



NO. 68 RAILWAY 

 500 VOLTS. 



TOR 



QEAR RATIO, 14 TO 68. WHEELS, 33" 



CONTINUOUS CAPACITY, 35 AMPERES AT 300 VOLTS, 



OR 33 AMPERES AT 400 VOLTS. 



Fig. 94. 



The general trend of the speed-torque curve of the series 

 motor supplied from constant voltage mains, as shown in Fig. 93, 



