Cause: Control voltage fault comes when 24 V DC is overloaded due to incorrect wiring of control card. The external devices connected to the 24 V DC output of the drive might be drawing excessive current, causing the voltage to drop.

danfoss al 47 alarm indicates Control voltage fault. This means that the drive has detected that the 24 V DC supply voltage on the control card has dropped below 18 V DC.

Troubleshooting Steps:

Follow these steps to correct danfoss al 47 alarm:

• Check External Load on 24 V DC Supply.
• Verify External 24 V DC Backup Supply.
• Inspect Drive's Power Card.
• Check Control Card Connections.