Speed & power – how do I operate my pneumatic motor?

20 octobre 2017

Handling a compressed air motor is relatively straightforward. It’s simply a question of knowing a few key points that we’ll share with you now. Speed, power, torque – we’ll explain everything! Pneumatic motors are very flexible – the speed can be adjusted by varying the air supply volume relative to your needs; as for the torque and power, they can be adjusted by varying the air pressure.


Download Air Motor Training Presentation


How do I vary the speed of my pneumatic motor?

The speed of a pneumatic motor automatically adapts to the load that’s applied. When no torque is applied, the motor operates at free speed. As the torque increases, the speed slows. A pneumatic motor achieves maximum power when it operates as close as possible to its nominal (free) speed – this is where it gives optimum performance. However, you can choose an alternative operating position, before or after the maximum power position – in fact, the preferred position is determined by the type of application for which the motor is to be used.

The other way to modulate the speed of a pneumatic motor is to vary the air flow rate, by placing an air flow limiter on the motor’s collected exhaust. And this can be done without any notable loss of power.

If you need to work at a low speed, or even a very low speed, we have already designed made-to-measure motors with torque limiters for clients in the nuclear, aeronautical and chemical industries.

How do I control the power of my pneumatic motor?

The power of a compressed air motor is dependent on the air supply pressure. For a constant air supply pressure, pneumatic motors work on a linear torque/speed relationship. Nevertheless, by simply regulating the air entering the motor, it’s easy to modulate a pneumatic motor’s operating torque. Modec motors function with a pressure that can vary between 4 and 6.2 bars.

To regulate the air supply pressure, we strongly advise using an FRL unit (filtration, regulation, lubrication) or, even better, a SAT box (safety air treatment). The SAT box is a safety device that protects both your employees and your equipment. It integrates an FRL unit, with additional safety measures incorporated:

  • Emergency stop button
  • Lock key (optional)
  • Automatic evacuation of the downstream circuit
  • Detection of drops in pressure and automatic air supply cut-off


As for the FRL unit, it filters/dries and lubricates the compressed air, ensuring the motor performs well. It also allows you to control the pressure of the air feed and, in turn, the performance of the actuator (maximum torque).

With these two principles in mind, you have all the information you need to understand how to use your compressed air motor. But if you want to know more, don’t hesitate to request a free consultation.

Air motor training presentation link to dowload

Marie-Charlotte Messier
Marie-Charlotte Messier

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