Material:		- Housing: Anodized aluminum, - Shaft: Steel ETG 100, - Blades: Special synthetic material with high durability
Temperature range:		-20 °C...+80 °C (there is a danger of icing up at temperatures of less than)
Pressure range:		0.5 bis 7 bar
Medium:		Filtered, dry, and oiled compressed air, oil quantity approx. 3 to 4 drops per m³ of compressed air (Motors for oil-free operation are available upon request).

• Flexible
  Adapts its speed and torque to the load at hand and can be stalled without being damaged (stall-proof).
  
• Adjustable
  Torque, speed, and turning direction is easily adjustable. Torque and speed are infinitely variable via air pressure or air quantity.
• Solid
  Infinitely variable switching and 100 % start-up duration at maximum performance. Performance reserves, as commonly required, are obsolete. If there should be an overload after all, the speed decreases until a balance between target momentum and speed has been achieved.
  
• Problem-free
  The internal pressure for each motor part is higher than the external one. This prevents foreign particles from intruding. After the technical external conditions have been released the motor can also be operated submerged in water.
• Maintenance-friendly
  Few moving parts (only the rotors are subject to wear) and thus maintenance-friendly.
• Compact
  A performance density superior to most other motors: Approx. 30 % smaller than a comparable asynchronous electrical motor.
• Easy start-up
  Contrary to traditional motors with an air hole system, leave springs press the rotors of our motors against the cylinder wall during standstill. This ensures a safe start-up, even if the pressure is low.
  

Fig. 1

General (Fig. 1)

The compressed air motor is one of the most robust and versatile drives available for construction today. It is infinitely variable across a wide rev range and offers its highest torque when it is most needed, during start-up.
The performance of the compressed air motor depends on the flow pressure, which is infinitely variable via pressure controller or throttles. With a consistent input pressure, non-controlled motors have a linear relationship between speed and torque. Contrary to traditional motors with an air hole system, blade springs press the rotors of our motors against the cylinder wall during standstill. This ensures a safe start-up, even if the pressure is low.

Fig. 2

Performance (Fig. 2)

The compressed air motor performance is made up of torque and speed. All non-controlled compressed air motors have about the same characteristic performance curves, whereas the highest performance is reached at approx. 50 % of the idling speed. Here the prevailing speed or torque is considered the nominal speed or nominal torque.
If the motor is burdened past the nominal torque, speed and performance decrease accordingly until the highest torque (stalling torque) is reached shortly before the motor stops. The stalling torque is approx. 200 % of the nominal torque.
If the motor starts up strained, the min. start-up torque is also the max. permissible torque, ensuring that the motor can restart. The mininum start-up torque is approx. 150 % of the nominal torque of the compressed air motor.

Fig. 3

Fig. 4

Controls (Fig. 3 and 4)

For speed reduction throttle valves can be installed on air intake and outlet, or a pressure controller on the air intake of the motor (Fig. 3).
Intake throttle: The speed decreases and simultaneously the min. start-up torque is also reduced, so is the air consumption. Recommended for all applications where the min. start-up speed is secondary and the torque is to be reduced.
Output throttle: The torque decreases and the min. start-up speed only decreases slightly, while the air consumption almost remains the same.
Pressure control: The torque is reduced without the speed being reduced too much. (Fig. 4)


All data for the compressed air motors refers to 6 bar. The chart below shows the changes in performance, nominal speed, nominal torque and air consumption when a motor is run with higher or lower pressure:

Rotating piston air motor - sectional view


Seleting the right motor (Fig. 5)

1. Determining the parameters

• Is it a reversible or a non-reversible motor?
  
• How much torque is required for which speed?
  
• Is it a stall-proof or a non-stall-proof motor?

Non-stall-proof motors can only be operated up to max. torque and should be protected against overload with a safety clutch.


2. Calculating the required performance

Formula

The min. performance for the compressed air blade motor should be 314 Watt. Thus, the models in Series RDU 400 (reversible) or RDR 550 (clockwise rotating) can be considered.
The nominal speed should be as close to the required working speed (300 U/min.) as possible. In consideration of these facts the selection can be limited to models RDU 400/240 (reversible) and RDR 550/275 (clockwise rotating).
Once the motor has been selected it can be adapted to the exact requirements by ­adapting the operating pressure.


3. Determining the operating pressure
The operating pressure for the motor can be calculated by entering ratio parameters
M1/M_nom and n1/n_nom in the diagram (Fig. 5). For nominal speed and torque, refer to the charts on the following pages.

Formula

Model RLA-0400-0480: M_nom = 15.9 Nm, n_nom = 240 U/min., M1 = 10 Nm, n1 = 300 U/min.



Model RXA-0550-0550: M_nom = 19.1 Nm, n_nom = 275 U/min., M1 = 10 Nm, n1 = 300 U/min.



Based on the ratio parameters and after entering and reading in the diagram at the

Fig. 5