The New Student's Reference Work/Motor

Mo′tor is any mechanical device by means of which energy is converted into motion. A windmill, used for driving a wheel or working a pump, is sometimes called an aeromotor. A machine by which the pressure of water in city mains is made to operate mechanical devices is usually called a water-motor. Motors for the use of compressed air have of late years been much used, especially for the propulsion of street-cars. But the name is now most frequently applied to devices for the conversion of static into dynamic electricity. Motors operated by electricity have been devised to propel everything from a bicycle to a locomotive. Electric power is sometimes conveyed to the motor from a waterfall and sometimes from a storage battery. In any simple electric motor one finds a field-magnet, consisting of various coils of insulated wire on soft iron cores. These are connected by a yoke; and lines of force are developed around the pole pieces when a current of electricity is run through the coils. Within these lines of force rotates the armature. Of late, through improved devices, power is conveyed long distances as from Niagara Falls (q. v.) to Buffalo; and power is conveyed to thousands of motors which operate innumerable mechanisms at a distance from the source. The discovery that natural forces can be made to store electric forces, which may in turn be reconverted into dynamic electricity at the other end of the wire by means of an electric motor, is one of the greatest discoveries of the 19th century.