Mains phase failure

What does F-06 mean?

A phase failure in the 3-phase mains supply or an under-voltage condition has occurred, leading to an immediate switch-off with inhibit. This protects the inverter from operating with an unbalanced or insufficient power supply. Continuous operation under these conditions can stress and damage the inverter and motor.

• Loss of one or more phases in the incoming 3-phase AC supply due to utility issues or upstream circuit breaker trip.
• Under-voltage condition on one or more phases (e.g., below 340V for a 400V system) caused by heavy load transients or grid instability.
• Loose connection at the inverter's L1, L2, L3 input terminals or at an upstream main contactor.
• Blown fuse in one phase of the incoming mains supply line to the inverter.
• Inverter input voltage monitoring circuit fault, reporting incorrect phase status.

Click steps to track your progress.

1. 1

   Measure the voltage between L1-L2, L2-L3, and L3-L1 at the inverter's input terminals (U, V, W or L1, L2, L3) using a multimeter to verify balanced phase voltages.

2. 2

   Inspect upstream circuit breakers, fuses, and main contactor for trips, blown elements, or signs of damage in the mains supply path to the inverter.

3. 3

   Tighten all screw terminals at the inverter input (L1, L2, L3) and the upstream main contactor to ensure proper electrical contact.

4. 4

   Verify the inverter's undervoltage trip threshold parameter (e.g., P0-94, P2-01) matches the incoming supply voltage and application requirements.

5. 5

   Monitor the grid voltage stability for fluctuations or sags using a power quality analyzer over a period.