Editing Engine (section)

=== Electric motor ===
{{Main|Electric motor|Electric vehicle}}
An ''electric motor'' uses [[electrical energy]] to produce [[mechanical energy]], usually through the interaction of [[magnetic fields]] and [[electrical conductor|current-carrying conductors]]. The reverse process, producing electrical energy from mechanical energy, is accomplished by a [[Electrical generator|generator]] or [[dynamo]]. [[Traction motor]]s used on vehicles often perform both tasks. Electric motors can be run as generators and vice versa, although this is not always practical.
Electric motors are ubiquitous, being found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, [[power tools]], and [[hard drive|disk drives]].  They may be powered by direct current (for example a [[battery (electric)|battery]] powered portable device or motor vehicle), or by [[alternating current]] from a central electrical distribution grid. The smallest motors may be found in electric wristwatches. Medium-size motors of highly standardized dimensions and characteristics provide convenient mechanical power for industrial uses. The very largest electric motors are used for propulsion of large ships, and for such purposes as pipeline compressors, with ratings in the thousands of [[watt (unit)|kilowatts]]. Electric motors may be classified by the source of electric power, by their internal construction, and by their application.
[[File:Electric motor.gif|thumb|Electric motor]]
The physical principle of production of mechanical force by the interactions of an electric current and a magnetic field was known as early as 1821. Electric motors of increasing efficiency were constructed throughout the 19th century, but commercial exploitation of electric motors on a large scale required efficient electrical generators and electrical distribution networks.

To reduce the electric [[energy consumption]] from motors and their associated [[carbon footprint]]s, various regulatory authorities in many countries have introduced and implemented legislation to encourage the manufacture and use of higher efficiency electric motors. A well-designed motor can convert over 90% of its input energy into useful power for decades.<ref>{{cite web |title=Motors |publisher=American Council for an Energy-Efficient Economy |url=http://www.aceee.org/topics/motors |archive-url=https://web.archive.org/web/20121023182642/http://aceee.org/topics/motors |archive-date=2012-10-23 }}</ref> When the efficiency of a motor is raised by even a few percentage points, the savings, in [[kilowatt hour]]s (and therefore in cost), are enormous. The electrical [[Efficient energy use|energy efficiency]] of a typical industrial [[induction motor]] can be improved by: 1) reducing the electrical losses in the [[stator]] windings (e.g., by increasing the cross-sectional area of the [[Electrical conductor|conductor]], improving the [[Inductor|winding]] technique, and using materials with higher [[Electrical conductivity|electrical conductivities]], such as [[copper]]), 2) reducing the electrical losses in the [[Rotor (electric)|rotor]] coil or casting (e.g., by using materials with higher electrical conductivities, such as copper), 3) reducing magnetic losses by using better quality magnetic [[steel]], 4) improving the [[aerodynamic]]s of motors to reduce mechanical windage losses, 5) improving [[Bearing (mechanical)|bearings]] to reduce [[friction loss]]es, and 6) minimizing manufacturing [[Engineering tolerance|tolerances]]. ''For further discussion on this subject, see [[Premium efficiency]]).''

By convention, ''electric engine'' refers to a railroad [[electric locomotive]], rather than an electric motor.