A4/W4 - Mains Phase Loss fault in danfoss drive

A4/W4 - Mains Phase Loss fault in danfoss drive

Cause: A phase is missing on the supply side, or the mains voltage imbalance is too high. This can also indicate a fault in the input rectifier.
Solution:

• Measure all three input phases of the incoming power with a voltmeter to ensure they are balanced and present.
• Inspect for blown input fuses and replace if necessary.
• Check the AC line contactor and the input rectifier assembly for any signs of damage or failure.
• Ensure all input power wiring is tight and secure.