Electrical motors are devices that convert electrical energy into mechanical energy. Electric meters use electric motors and counting devices to translate current flow into a measured use of electrical energy. Electrical motors perform the inverse transformations performed by electrical generators (i.e., the transformation of mechanical energy into electrical energy). To a limited extent, all electrical motors perform these inverse transformations as they operate to produce a counter or back electromotive force.

The modern form of the electrical generator evolved from the research and engineering work of nineteenth-century Danish scientist Hans Christian Ørsted and English physicist Michael Faraday who developed a rotator (later to be known as an electric motor) containing a conductive (i.e., electrical current carrying) wire rotating around a magnet. Working independently, American inventor Joseph Henry also developed an early model of the electric motor. Although it was...