William Shockley (seated), John Bardeen (standing, left), and Walter H. Brattain doing transistor research at Bell Telephone Laboratories (New York, 1948).(Corbis Corporation)

Electric motors are everywhere. These ubiquitous devices come in a wide variety of sizes and power outputs, ranging from a fraction of a watt to huge multikilowatt applications. Tiny ones operate computer disk drives, power windows/mirrors, and windshield wipers; moderate-sized ones run appliances such as fans, blenders, electric shavers, and vacuum cleaners; a large drive pumps, elevators, sawmills, and electric trains and vehicles.

There has been not only growth in the total number of electric motors (more standard appliances in use), but also a proliferation in their use for new, novel applications. Both trends will continue to increase demand for the electricity to run electric motors. In the United States, electric motors are responsible for consuming more than half of all...