Editing Engine (section)

=== Physically powered motor ===
Some motors are powered by potential or kinetic energy, for example some [[funicular]]s, [[gravity plane]] and [[ropeway conveyor]]s have used the energy from moving water or rocks, and some clocks have a weight that falls under gravity. Other forms of potential energy include compressed gases (such as [[pneumatic motor]]s), springs ([[clockwork motor]]s) and [[Elastic band#Model use|elastic bands]].

Historic [[military]] [[siege engines]] included large [[catapult]]s, [[trebuchet]]s, and (to some extent) [[battering ram]]s were powered by potential energy.

==== Pneumatic motor ====
{{main|Pneumatic motor}}
A ''pneumatic motor'' is a machine that converts potential energy in the form of [[compressed air]] into [[mechanical work]]. Pneumatic motors generally convert the compressed air to mechanical work through either linear or rotary motion.  Linear motion can come from either a diaphragm or a piston actuator, while rotary motion is supplied by either a vane type air motor or piston air motor. Pneumatic motors have found widespread success in the hand-held tool industry and continual attempts are being made to expand their use to the transportation industry. However, pneumatic motors must overcome efficiency deficiencies before being seen as a viable option in the transportation industry.

==== Hydraulic motor ====
{{main|Hydraulic motor }}
A ''hydraulic motor'' derives its power from a [[pressure|pressurized]] [[liquid]]. This type of engine is used to move heavy loads and drive machinery.<ref>{{cite web
 |url=http://reference.howstuffworks.com/hydraulic-engine-encyclopedia.htm
 |title=Howstuffworks "Engineering"
 |publisher=Reference.howstuffworks.com
 |date=2006-01-29
 |access-date=2011-05-09
 |archive-url=https://web.archive.org/web/20090821175006/http://reference.howstuffworks.com/hydraulic-engine-encyclopedia.htm
 |archive-date=2009-08-21
}}</ref>

====Hybrid====
Some motor units can have multiple sources of energy. For example, a [[plug-in hybrid electric vehicle]]'s electric motor could source electricity from either a battery or from [[fossil fuels]] inputs via an internal combustion engine and a generator.