Vanemotors consist essentially of a rotor which revolves in an eccentrically offset perforation of the rotor cylinder. The vanes form working chambers, the volume of which increases in the turn direction. As the compressed air expands, the pressure energy subsequently transforms into kinetic energy, thereby producing the rotary motion.

Airmotors that are designed to rotate in one direction only, have more rotational angle for the air to relax. Therefore the non-reversible vanemotors reach a higher power output and higher speeds than reversible airmotors.