Mains phase loss

What does 4 mean?

A phase is missing on the supply side, or the mains voltage imbalance is too high. This message can also appear if there is a fault in the input rectifier. Options for handling this are programmed in parameter 14-12 Function at Mains Imbalance.

• Blown fuse or tripped circuit breaker on one of the incoming mains phases (L1, L2, or L3) upstream of the drive.
• Interruption in the upstream power supply grid causing a complete or partial phase loss.
• Loose connection or damaged cable on one of the incoming mains phases at the drive's input terminals (e.g., X1:L1).
• Faulty input rectifier bridge within the drive (e.g., one or more diodes shorted or open).
• Significant voltage imbalance (e.g., >3%) across the incoming mains phases due to utility issues or heavy unbalanced loads.

Click steps to track your progress.

1. 1

   Measure the incoming line-to-line voltages (L1-L2, L2-L3, L3-L1) at the drive's input terminals (e.g., X1:L1, X1:L2, X1:L3).

2. 2

   Check all upstream fuses and circuit breakers (e.g., F1, F2, F3) for continuity and proper operation.

3. 3

   Inspect all connections of the incoming mains power cables at the drive's input terminals for tightness and corrosion.

4. 4

   Verify the voltage balance across the incoming phases; ensure no phase deviates by more than 2% from the average phase voltage.

5. 5

   If an internal rectifier fault is suspected, measure the DC-link voltage (e.g., terminals +DC, -DC) for excessive ripple or asymmetry.