AC Output Over Voltage

What does F2 mean?

This Escalating Automatic Fault indicates an AC over-voltage shutdown (above 135 V). If it occurs 3 times in 30 seconds, it becomes a manual fault, meaning the inverter has repeatedly shut down to protect connected loads.

• Regenerative load (e.g., crane, elevator) feeding power back into the inverter, causing DC bus and then AC output over-voltage.
• Over-sizing of inverter for a small load, leading to poor voltage regulation under light load conditions.
• Faulty voltage regulation circuit or output stage components within the inverter.
• Improperly configured inverter output voltage settings (e.g., parameter P3-10 set too high above 135V).
• Utility grid over-voltage condition feeding back into grid-tied inverter systems.

Click steps to track your progress.

1. 1

   Measure AC output voltage at inverter terminals L1, L2, L3 (or L1, N) using a true RMS multimeter under no-load and full-load conditions.

2. 2

   Verify inverter output voltage configuration (e.g., Parameter P3-10, P3-11) is set correctly for the application's nominal voltage (e.g., 120V or 240V).

3. 3

   Check for regenerative load conditions and verify proper functioning of braking resistors or regeneration units (e.g., measure resistance of braking resistor).

4. 4

   Monitor utility grid voltage at the inverter input terminals (L1, L2, L3, N) to confirm it remains below 135V nominal.

5. 5

   Perform a factory reset of inverter parameters (e.g., Parameter P0-01 to "Reset") and reconfigure essential settings to eliminate configuration errors.