Stall Prevention (Overcurrent)

What does OL mean?

This alarm indicates that the FR-A800 inverter's stall prevention function has activated due to an overcurrent condition, typically during acceleration, constant speed, or deceleration. The inverter attempts to prevent a trip by limiting the output current, which may result in reduced speed or torque. It is often a precursor to an OC trip if the condition persists.

• Sudden load changes or mechanical issues causing the motor to draw excessive current.
• Acceleration time (F010 (Pr.7)) or deceleration time (F011 (Pr.8)) set too short, causing rapid current changes.
• Stall prevention level H500 (Pr.22) is set too low for the application's operating conditions.
• Motor or drive capacity is undersized for the application.
• Excessive supply voltage sag or fluctuation.

Click steps to track your progress.

1. 1

   Inspect the mechanical load for binding, excessive friction, or sudden load increases. Check for rail joint issues or reduction gear/wheel problems if applicable.

2. 2

   Adjust acceleration time (F010 (Pr.7)) and deceleration time (F011 (Pr.8)) to longer values to reduce current peaks.

3. 3

   Increase the stall prevention level H500 (Pr.22) (Stall prevention operation level) to allow higher current draw, but do not exceed motor or FR-A800 inverter ratings significantly.

4. 4

   Verify the motor and inverter capacities are appropriate for the application.

5. 5

   Monitor the power supply voltage for fluctuations or sags.