Pneumatic Motor Not Working? Most Common Failures and How to Fix Them

Pneumatic motors are known for their simplicity and robustness.

Unlike electric motors, most issues can be resolved easily—if you know what to look for. Here’s a quick guide to diagnosing and fixing the most frequent failures.

Step One: Proper Run-In and Setup

Motor Doesn't Start After Connection?

• 1. Power Supply or Porting Issue

  Check the air source first:

  • ❌Incorrect port connection on the distributor can prevent non-reversible motors from starting at all.

  • ❌A reversible motor may still run with wrong porting, but at reduced power.

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  2. Excessive Load on the Shaft

  • • The motor might be undersized for the required torque.

    • Review the torque-speed curve to verify sizing.

     

• Motor Runs but Stops Quickly or Loses Power?

3. Poor Air Supply Quality

• ❌Low pressure or flow may limit motor performance.

• ❌Contaminated air can introduce particles into the rotor → risk of jamming, scratches on the stator, or premature wear.

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• Lack of lubrication also leads to power loss.

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👉 Solution:
Install a proper FRL unit (Filter, Regulator, Lubricator) to ensure dry, clean, and lubricated air.

Motor Stopped After Running for Hours?

4. Internal Wear or Corrosion

• Humidity or oil-free air can corrode internal components.
  Overpressure may damage the gearbox or wear vanes prematurely.
   
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5. Assembly Error After Maintenance

• Improper reassembly (e.g., needle bearings misaligned, no oil added) can cause internal damage.
  Check that all parts are correctly positioned and lubricated.
   

• Summary Table – Issues, Causes, and Fixes

Most pneumatic motor failures are preventable or fixable with a quick inspection and basic maintenance.

Use clean, lubricated air, ensure proper sizing, and follow correct servicing procedures to maximize reliability and extend motor life.