Electric motors account for about half of all energy consumption in the US. They can be found just about everywhere; in fact, motors control the majority of moving parts in machines. Being so widespread, it is possible to see substantial energy savings with just a small improvement in efficiency.

A very comprehensive overview of electric motors can be found on the Machine Design Web site (1). It describes five common types of motors and how they operate. Some material is fairly technically oriented. For a more basic introduction, the Western Electric company (2) discusses the underlying theory and construction of electric motors. This is more suited for early high school students and above. The Department of Energy's Office of Industrial Technologies (3) provides many documents related to best practices for motor systems. Many energy saving techniques are outlined in these tip sheets and technical publications. Similar information is contained in this Australian Web site (4). Specific issues, such as motor rewinding, are discussed to correct many common mistakes made when conducting maintenance and repairs. Some interesting facts about general motor use and the "Premium-Efficiency Motor Initiative" are given on this Web site (5). The short article demonstrates that industry and government organizations realize the importance of improving motor efficiency. Along these same lines, a project is underway that hopes to make copper motor rotors economically feasible (6). Current rotors are made with aluminum, but switching to copper would help make motors more energy efficient. The Web site has many documents on the status of the project. The University of Missouri at Rolla has a research group investigating piezoelectric motors (7). Some details of piezoelectric motor design and manufacturing are given. A news article from March 2002 (8) tells of a revolutionary new kind of electric motor. This breakthrough could make electric cars cheaper than gasoline fueled vehicles.