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How to perform maintenance on your air motor?

Olivier Ben Soussan
by Olivier Ben Soussan on Mar 11, 2020 2:09:10 PM

You can ensure a high level of performance from your air motor for many years if it is used and maintained properly. 

The good news is that servicing and maintaining an air motor is not difficult. Basically, there are two key elements to keep a close eye on: lubrication and filtration. Monitoring these two aspects will keep your air motor running smoothly and ensure optimum performance.

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What happens if the performance of your air motor changes?

  • The pallets are worn

The pallets guarantee the impermeability between the rotor and stator and thus seal the compression chambers of the motor. When they are used, the sealing is no longer ensured. The efficiency becomes poor and therefore the torque is reduced. When they are broken, the motor no longer starts or locks up. And if the motor does manage to start, vibrations are observed. 

  • Ball bearings

Ball bearings ensure the rotation of the rotor in the stator for the pneumatic part and the correct operation of the reduction part. When they are used the bearing can move, and we can hear scratching noises as well as observe difficult rotation. This has a direct impact on the efficiency of the motor.

  • The filters

As on a car, filters ensure the quality of the air but also of the lubrication inside the motor. If there is dirt in the filter, the engine is poorly lubricated. If dust enters the motor, the air flow rate and therefore the motor's efficiency is reduced. 

Wear and tear of any of the components described above can lead to a chain reaction. For example, poor filtration will lead to premature wear of the vanes, which during operation of the motor produce vibrations that will wear out the bearings prematurely.

There can be several reasons for the poor condition of these different pneumatic parts:

  • High use of the air motor

The air motor wears down more quickly at its vanes if it works at a torque very close to the stall torque. In this case the vanes may break. If the air motor is operated close to free speed (very fast) then the vanes will wear faster.

  • A defective air network

A dusty or dirty air network or a non-conforming network pressure can impact the pneumatic parts of your motors.

Download the pneumatic motor maintenance manual

Maintenance of a standard air motor 

  • Maintenance of an air motor with lubrication: lubricate your air motor! 

The most important maintenance step is to make sure that the air motor is well lubricated, using products specifically adapted to the needs of air motors. Lubrication in the air protects the blades, while the grease inside the gearbox protects the gears.

It is important to use the right oil to lubricate an air motor. An air motor constantly generates cold due to the expansion of air in the pneumatic part. The oil must be liquid enough to lubricate even when the motor is operating at very low temperatures. The viscosity and technical characteristics of the oil are therefore essential.

Good lubrication also helps to reduce the possible effects of moisture inside the engine by preventing or minimizing the effects of corrosion.

Using the wrong type of oil presents a real risk. Incomplete lubrication of all necessary areas will sooner or later lead to reduced performance - reduced starting speed or torque - and potential damage to the motor's vanes, or worse, to the cylinder (an expensive part to replace).  

The oil is supplied as a spray in the supply air. When the engine has not been running for a long time, there is no oil present and it is advisable to insert a few drops directly into the motor intake port before starting. Likewise, before stopping the motor, it is a good idea to run it for a few seconds with well-lubricated air so as to deposit a protective layer on the internal parts. 

The oil used in an air motor has three main functions:

  • The reduction of friction between mechanical parts. 

A rotor rotates at a speed of about 10,000 revolutions per minute. Without a suitable lubricant, heating and wear of the internal parts of the motor would quickly cause problems! 

  • The protection of internal parts when the motor is not moving. 

The oil deposit left by the last use protects the parts against corrosion and dust

  • The sealing of the decompression chambers in the cylinder. 

It is less well known, but oil contributes to the sealing of the decompression chambers in the cylinder, which is critical for the good efficiency and performance of the motor.

Which oil to choose? 

There are several groups of oils, including the mineral oil family and the synthetic oil family. Each type of oil has specific properties that must be used correctly according to the constraints of the application. 

MODEC oil combines these intrinsic properties with the specificity of additives rigorously selected to bring its performance level to the top of current technology. It thus preserves each friction point from degradation phenomena, spares maintenance interventions and actively contributes to reducing the motor energy consumption.

  • Maintenance of an air motor with lubrication: check the filtration system.

Check the filters regularly and replace them if necessary. This is not a major expense, so it is always better to change the filters if necessary rather than risk damage to the interior of the motor due to fine particles.

You will need to check and possibly replace the vanes after about 1,000 to 2,000 hours of use and add grease to the gearbox after about 1,000 hours.

Some filtration tips 

If small dust or metal particles enter the air motor, they can damage the vanes and potentially degrade the cylinder surface. Installing a filter just before the air inlet point reduces the risk of particles entering the motor. 

If they enter, the motor will lose speed, torque and therefore power. Replacing filters is easy and costs very little, unlike replacing a cylinder, so keep an eye on the condition of your filters!

 

Maintenance of an air motor without lubrication

For air motors without lubrication, good maintenance means regular monitoring of the air filtration system and the use of perfectly dry air. In the absence of oil inside the engine, metal parts must be kept dry to ensure high efficiency. The key is to ensure at all times that only extremely dry air enters the motor.

The vanes inside the air motors without lubrication should be checked after about 80 hours of use.

What should I do if my air motor power drops?

You must act quickly. If you notice a change in the performance of your air motor, don't wait in the hope that it will regulate itself. It's probably a problem that's easy to correct, but if you don't fix it, this small problem can have other effects on the operation of the motor. 

Here's a checklist to help you identify where the problem with your air motor's power loss may be coming from:

  • Check the lubrication system

A quick and simple check for standard engines is to place a cloth or dry rag in the engine exhaust and check for oil traces. If lubrication levels are correct, there should be visible oil. If there isn't, either you need to top up the oil or it is an indication that there is a problem in the lubrication system. If you notice water marks on the fabric, this could also indicate a potential problem. 

  • Check the filter 

Is it partially clogged with dust particles? 

  • Check that the rotor rotates freely. 

- If the rotor rotates freely, but the motor does not work as it should, this suggests a potential problem in the planetary gearbox located in front of the motor, just after the pneumatic part. Check that there are no abnormalities with the air inlet - is the connection properly installed? Is the air pressure volume at the right level?... 

Tip: there is a small screw on the back of Modec air motors that you can turn to move the rotor without having to open the motor. 

-If the rotor does not rotate freely: the problem is inside the pneumatic part of the motor. In this case, you must check that the bearings, the vanes and the cylinder are all in good working order.

The important thing was to identify the problem before starting to repair. This can avoid replacing parts unnecessarily in the first place, as well as saving the operator time, saving the company money, and avoiding further damage. For example, if the bearings are broken, the motor will lose power but other parts will not be affected. However, if the cylinder is altered it could damage the pallets which are less solid. 

For more advice and information, feel free to download our complete guide!

manual-for-the-maintenance-of-a-pneumatic-motor

 

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