Line phase supervision

What does F11 mean?

The current measurement system has detected an imbalance where one phase current is either missing or significantly different from the other phases. This indicates an issue with the power delivery to the motor. Operating with unbalanced phases can lead to motor overheating and drive component stress.

• Missing input phase: Similar to F10, but specifically detected by current imbalance rather than voltage.
• Blown input fuse or tripped circuit breaker in one phase, causing current to flow through only two phases.
• Imbalance in the supply voltage, causing disproportionate current draw across phases.
• Loose or high-resistance connection in one of the input power phases to the drive.
• Internal current sensor (CT) malfunction in the drive for one of the input phases.

Click steps to track your progress.

1. 1

   Measure the incoming line voltage phase-to-phase (L1-L2, L2-L3, L3-L1) at the drive input terminals (e.g., Menu 1-05 'Input Voltage') using a true RMS voltmeter. Check for significant voltage imbalance (>2%).

2. 2

   Inspect all input fuses and circuit breakers for continuity using a multimeter (ohmmeter). Replace any blown fuses with the correct rating and type.

3. 3

   Verify tightness and condition of all input power connections at the main breaker, contactor, and drive input terminals. Check for discoloration indicating overheating.

4. 4

   Observe the input current on the drive's display (e.g., Menu 1-07 'Input Current') during operation. Compare current values across L1, L2, L3.

5. 5

   If voltage and connections are confirmed good, the fault might indicate an internal issue with the drive's current measurement circuitry.