1. High power to weight/size ratio
2. Simple speed control
3. Suitable for use in hazard area
4. Easy to reverse
5. Extremely robust
6. Simple installation
7. Torque remains fairly constant.
•These are the most popular and widely used displacement motors. Vane motors have most compact and versatile construction and are generally available in powers upto 5kW with speeds ranging from 200 to over 30,000 rev/mm Fig. shows the interval construction of typical vane motor.
Fig. Vane motor.
•A slotted rotor rotates eccentrically within the chamber formed by the cylinder and end plates. Since the rotor is smaller in diameter and eccentric to the outer chamber, a crescent shaped chamber is formed.
•The rotor is provided with vanes which are allowed to move freely in and out of the slots in the rotor. These vanes divide the chamber into separate compartments each of a different size. Compressed air is admitted into the compartments at a point where its volume is enlarging.
•The air pressure acting on the inlet side of the vane creates a force, and hence a torque or turning moment results. The actual quantity of air supplied determines the speed of motor.