THE ELECTRIC MOTOR 



499 



The Electric Motor. In the dynamo the coils of wire 

 are revolved in a magnetic field by some mechanical power, 

 and electricity is generated in the coils. In the motor the 

 process is reversed ; electricity is passed through the coils of 

 the motor. This causes them to revolve in a magnetic 

 field and to produce mechanical power. In appearance and 



Courtesy of Chicago, Milwaukee and St. Paul Railway 

 ELECTRIC LOCOMOTIVE 



One of the locomotives which obtains its power from the plant pictured 

 opposite. The most powerful electric locomotive in the world. 



make-up the two machines are similar, but their work is 

 different. The dynamo generates an electrical current ; the 

 motor uses an electrical current. 



In the running of the ordinary street car, the motor and 

 the dynamo supplement each other. At the power house 

 are dynamos run by any convenient kind of mechanical 

 power. The electricity that is generated is collected and 



