Mains Phase Missing

What does F00020 mean?

One or more of the three-phase AC input power lines to the drive is disconnected or has failed while the drive is enabled and under load. This can lead to unbalanced operation, component stress, and potential damage to the inverter or motor if not corrected, causing reduced performance and premature equipment failure.

• One or more input fuses (e.g., line fuses L1, L2, L3) are blown or tripped.
• Loose or disconnected wiring on the main input power terminals (e.g., R, S, T or L1, L2, L3) at the drive or upstream breaker.
• Failure of an upstream power component like a contactor (e.g., main contactor K1) or circuit breaker.
• Unbalanced grid voltage supply due to external load changes or utility issues.
• Incorrectly sized input choke (e.g., line reactor) causing excessive voltage drop on one phase.

Click steps to track your progress.

1. 1

   De-energize the drive and verify the voltage across all three input phases (e.g., L1-L2, L2-L3, L3-L1) at the drive's input terminals using a multimeter.

2. 2

   Inspect all input fuses (e.g., gG-class fuses) for continuity and replace any blown fuses with identical ratings.

3. 3

   Check all main power connections at the drive's input terminals (e.g., R, S, T) and upstream power distribution for tightness and corrosion.

4. 4

   Verify the proper operation of any upstream contactors or circuit breakers (e.g., main breaker QF1) by checking their auxiliary contacts and coil voltage.

5. 5

   Monitor the incoming mains supply voltage stability over time for sags or dropouts using a power quality analyzer.