DC link voltage low

What does 6 mean?

The intermediate circuit voltage (DC) has dropped below the low-voltage warning limit, which is dependent on the frequency converter's voltage rating. The unit is still active, but operating with insufficient voltage could affect performance or lead to a trip.

• Incoming AC mains supply voltage dropping below the specified nominal input range (e.g., <340V for a 400V drive).
• Heavy load transients causing temporary voltage sags on the upstream supply network.
• Loose or corroded connections on the input power terminals (L1, L2, L3) causing excessive voltage drop under load.
• Undersized input power cabling leading to significant voltage drop under continuous motor load.

Click steps to track your progress.

1. 1

   Measure the incoming AC mains voltage at terminals L1, L2, L3 under load to confirm it stays within the frequency converter's specified operating range.

2. 2

   Verify the sizing of upstream circuit breakers and contactors to ensure they are not causing voltage drops under motor load.

3. 3

   Tighten all power connections at the drive input terminals (L1, L2, L3) and inspect for signs of corrosion or arcing.

4. 4

   Review parameter P1-20 (Mains Voltage) to ensure it is correctly set to the actual incoming supply voltage for accurate monitoring.