DC link voltage low

What does 6 mean?

The DC-link voltage is lower than the drive's low-voltage warning limit, which depends on the drive voltage rating. The unit remains active at this warning state, but a further drop could lead to an undervoltage trip.

• Low incoming mains voltage falling below the drive's nominal operating range (e.g., 360V instead of 400V).
• Transient voltage sag on the mains supply during heavy load starting or switching events upstream.
• Loose connection or high resistance in the incoming mains power circuit or input choke connections.
• Internal power supply issue within the drive causing incorrect DC-link voltage measurement.
• Heavy motor load causing excessive current draw and a subsequent voltage drop across internal components.

Click steps to track your progress.

1. 1

   Measure the incoming AC line-to-line voltage at the drive's input terminals (e.g., L1-L2, L2-L3, L3-L1) and confirm stability under load.

2. 2

   Monitor the DC-link voltage (e.g., via LCP or terminals +DC, -DC) during normal operation and load transients.

3. 3

   Inspect all connections of the incoming mains power cables at the drive's input terminals (e.g., X1) for tightness and corrosion.

4. 4

   Check for significant voltage drops across upstream contactors, fuses, or circuit breakers under full motor load.

5. 5

   Verify parameter P1-54 (Motor Rated Voltage) is set correctly for the application's actual motor and supply voltage.