A pneumatic motor is a machine which converts energy of compressed air into mechanical work. In industrial applications linear motion can come from either a diaphragm or piston actuator. For rotary motion a vane type air motor is used. Rotary motion vane type air motors are used to start large industrial diesel or natural gas engines. Stored energy in the form of compressed air, nitrogen or natural gas enters the sealed motor chamber and exerts pressure against the vanes of a rotor. Much like a windmill, this causes the rotor to turn a high rate of speed. Reduction gears are used to create high torque levels sufficient to turn the engine flywheel when engaged by the pinion gear of the air motor or air starter.