F004Type 1 fault (auto-reset) · Power sectionUsually repairable
PowerFlex 525 F004: UnderVoltage
What F004 means
The DC bus voltage inside the drive fell below its minimum.
Symptoms
Trips when the plant supply dips, at power-down, or when a large load starts nearby.
Is it repairable?
Yes, when the cause is inside the drive: pre-charge and capacitor faults are repaired at component level.
Common causes
- Low or interrupted incoming supply
- A blown or open input fuse
- A loose input terminal
- A failing pre-charge circuit or weak DC bus capacitors inside the drive
Safe checks
- 1Measure all three input phases under load
- 2Check the input fuses and terminal tightness
- 3Note whether it trips only when other equipment starts
Drives hold dangerous voltage after power-off. Checks should only be done by qualified personnel, with power isolated and the DC link discharged.
Reviewed by AutomIQ repair technicians. Code and name from the PowerFlex 520-Series Adjustable Frequency AC Drive User Manual.
Related PowerFlex 525 faults
- F005OverVoltage
- F007Motor Overload
- F008Heatsink OvrTmp
- F012HW OverCurrent
- F013Ground Fault
- F021Output Ph Loss