All you need to know about the use and control of a pneumatic motor

It’s very easy to use a compressed air motor. Firstly because they operate according to a very simple principle - for example, they can operate steadily with no need for a limit switch or for thermal protection. In effect, the motor simply stops when it reaches the end point, without causing any wear or tear and with no risk of breaking down. Secondly, because it’s really easy to control how a pneumatic motor performs – torque varies according to the pressure applied and speed according to air supply.

So, you don’t need to use complex and expensive electrical components to handle and control a pneumatic motor. This means you can stay within the bounds of compressed  air technology, making it easier to put in place solutions that are suitable for ATEX environments or for specific, restrictive environments such as humidity (no risk of corroding electric connections or components) or high temperatures (a pneumatic motor withstands high temperatures and gives off no heat).

Filter, regulate and lubricate before using

The few precautions you need to take are simple, but important:

• Guarantee the air quality – use a 40-micron filter to prevent particles damaging the pneumatic part of the motor.
• Control the pressure entering the motor – regulate the air pressure fed into the motor (3-6 bars).
• Lubricate the air – lubricating the air prevents corrosion and improves the sliding motion between components, thereby improving the motor’s performance and maximising its shelf-life.

Rotating the motor

A simple distributor carries the pneumatic energy to feed, or not, the entry opening of the compressed air motor. It can be activated manually, pneumatically or electrically. Like the contact switch associated with an electric motor, the distributor is the pre-actuator associated with a pneumatic motor. The choice of actuator is determined by the motor’s air consumption (flow rate). In general, the pressure required to operate a pneumatic motor is within a range of 4 to 7 bars. At this fairly moderate pressure level, you don’t need to invest in special equipment for air production – the air can be easily supplied via an existing air supply network.

For a reversible motor, i.e. a motor that can operate both clockwise and anti-clockwise, it’s best to use a 5/3 distributor (5 outlets and 3 positions) – the 5 outlets mean you can manage either the air feed or the air exhaust, according to which direction of rotation you require; the 3 positions enable you to select which way the motor rotates or a central position in which the motor is at rest.

For a one-directional motor, a straightforward 3/2 distributor (3 outlets and 2 positions) does the job, following the same principles.

Operating, handling and controlling a compressed air motor is therefore extremely easy and reliable because you can minimise the number of components put to work.