Overcurrent

What does OC mean?

The FR-A800 inverter has detected an instantaneous overcurrent condition in the output stage, exceeding its current limit. This can occur during acceleration, deceleration, or constant speed operation, and is a protective trip to prevent damage to the inverter's power devices (IGBTs) and the motor.

• Sudden, excessive load on the motor (e.g., mechanical shock, jam).
• Short circuit or ground fault in the motor, motor cable, or at the inverter output terminals.
• Acceleration time (F010 (Pr.7)) or deceleration time (F011 (Pr.8)) set too short, causing rapid current transients.
• FR-A800 inverter output MC (magnetic contactor) incorrect operation during run.
• FR-A800 inverter capacity is too small for the motor or load.
• Stall prevention level H500 (Pr.22) is set incorrectly or deactivated (H631 (Pr.154) set to '0').

Click steps to track your progress.

1. 1

   Power off the FR-A800 inverter and visually inspect the motor and mechanical load for any binding, obstructions, or damage.

2. 2

   Check motor windings and power cables for short circuits or ground faults using appropriate continuity and insulation tests. Measure phase-to-phase and phase-to-ground resistance.

3. 3

   Increase the acceleration time (F010 (Pr.7)) and deceleration time (F011 (Pr.8)) to allow for smoother transitions and reduce current peaks.

4. 4

   Verify parameter H500 (Pr.22) (Stall prevention operation level) is set appropriately, typically between 100% and 150% of the motor rated current. Ensure H631 (Pr.154) is not set to '0' (stall prevention invalid).

5. 5

   Check for correct operation of any output magnetic contactor (MC) and ensure it's not switching during FR-A800 inverter operation.

6. 6

   Review the FR-A800 inverter and motor sizing for the application.