Cooling fan
Common VFD, drive, UPS, and cabinet overheating failure point.
Allen Bradley PowerFlex Fault Codes — Quick Reference
Allen Bradley PowerFlex drives display fault codes on the integral keypad or HIM (Human Interface Module). The fault code format varies by drive family: PowerFlex 4/40 use F-prefix codes; PowerFlex 523/525 use F or numeric codes; PowerFlex 700/753/755 use numeric fault codes accessible via the keypad or DriveExplorer/Studio 5000 software.
| Code | Drive | Meaning | Common Fix |
|---|---|---|---|
| F002 | 4/40/523 | Auxiliary input fault | Check enable input wiring |
| F004 | 4/40/523 | Undervoltage | Check input power; transformer |
| F005 | 4/40/523 | Overvoltage | Decel ramp too fast; add braking resistor |
| F007 | 4/40/523 | Motor overload (OL) | Reduce load; check motor current |
| F012 | 40/523 | HW overcurrent | Check motor wiring; mechanical jam |
| F025 | 40/523 | DPI comm fault | Check HIM or comm module connection |
| F043 | 525 | Phase VW short | Check V-W motor wiring and motor |
| F063 | 40/523 | SW overcurrent | Check drive-to-motor wiring |
| F069 | 40/525 | PI feedback loss | Check feedback device wiring |
| F111 | 40/525 | External fault | Check fault input wiring and source |
| Fault 3 | 700/753/755 | Power loss | Check supply voltage |
| Fault 7 | 700/753/755 | Motor stalled | Check load; increase stall timeout |
| Fault 12 | 700/753/755 | HW overcurrent | Check wiring; mechanical jam |
| Fault 35 | 753/755 | Comms loss | Check EtherNet/IP or DeviceNet |
Most Common Codes
F007 / Fault 7: Motor Overload / Motor Stalled
The drive’s electronic overload (E-OL) tripped because the motor drew more current than its programmed limit for too long. First check: Is the motor actually stalled by a mechanical jam? Second: Is the motor FLA (Full Load Amps) programmed correctly in the drive? An incorrectly programmed FLA setting (too low) causes nuisance overload trips.
To check FLA programming on PowerFlex 40: Navigate to P031 (Motor NP FLA) and verify it matches the motor nameplate FLA. Adjust if needed.
To check FLA programming on PowerFlex 755: In Studio 5000, find parameter 28 (Motor NP FLA) in the Motor Control group.
F004 / Fault 3: Undervoltage / Power Loss
Input voltage dropped below the minimum threshold during operation. Common causes: a weak utility feed, a transformer undersized for the load, or a long run of undersized input wiring with voltage drop. Measure incoming voltage at the drive’s L1/L2/L3 terminals under load. On 480V drives, minimum is typically 342V (480 × 0.9 − 10%).
F005: Overvoltage
The DC bus voltage exceeded its limit. Usually caused by regenerative energy during fast deceleration. Solutions: (1) extend the deceleration time (parameter A441 on PF40, parameter 535 on PF700), (2) enable the built-in DC bus regulation if available, (3) add a dynamic braking resistor for high-inertia loads.
F012: Hardware Overcurrent
An instantaneous overcurrent condition tripped the drive. This is different from F007 (slow overload) — F012 is a fast peak-current trip. Causes: a motor winding shorted to ground, a phase-to-phase short in the motor cable, a seized bearing causing locked-rotor current, or a failed IGBT in the drive output. Use a megger (insulation resistance tester) to check the motor and cable before re-energizing.
F025: DPI Communication Fault
The DPI port (which connects the keypad or HIM module) has lost communication. On PowerFlex 4/40 drives, this often occurs when the HIM cover is vibrating loose from the drive door. Re-seat the HIM firmly onto the DPI port. If the fault persists without a HIM installed, check parameter 190 (DPI Fault Select) — if set to “Fault,” the drive faults when no HIM is present.
Fault 35: Communication Loss (PowerFlex 753/755)
The drive lost communication with the EtherNet/IP network or I/O scanner. Check: (1) Ethernet cable connection at the drive’s embedded EtherNet/IP port, (2) IP address configuration (verify in Studio 5000), (3) whether the PLC is running and the CIP connection is established. Fault 35 commonly occurs after a PLC reboot if the drive’s connection wasn’t set as “Configurable.”
Clearing Faults
- Manual clear: Press STOP key three times on PowerFlex 4/40; press the fault clear button on PF700/753/755 HIM.
- Auto-reset: Configure parameter 194 (Auto Rstrt Tries) to attempt automatic restarts after transient faults.
- Parameter: On PF40, set A094 (Fault Clear) to 1 to clear via parameter write.
Parts Often Needed
| Part | Notes |
|---|---|
| HIM module | PowerFlex 4/40: 22-HIM-A3; PF700: 20-HIM-A3 |
| Dynamic braking resistor | Size per drive HP; Rockwell catalog or third-party |
| Contactor / line reactor | Add if experiencing nuisance undervoltage trips |
Technician Tips
When diagnosing VFD faults, always check the drive’s fault history before resetting. Modern drives store the last 5-10 faults with the drive state at the time (running, accelerating, decelerating, stopped). An overcurrent fault that occurs only during acceleration points to incorrect motor data or mechanical binding. The same fault during deceleration suggests regeneration issues. A ground fault that clears after disconnecting the motor and returns when reconnected means the motor or cable insulation has failed.
Prevention: Schedule annual infrared scanning of drive cabinets. Loose power connections and failing capacitors produce heat long before they cause faults. A 5-minute scan can prevent hours of unplanned downtime.
Need Replacement Parts?
Before ordering, match the drive part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
When to Call a Pro
F012 (hardware overcurrent) and any fault accompanied by a burning smell or visible damage to the drive’s output stage require qualified drive service technicians. Replacing IGBTs and gate drivers inside a PowerFlex 700 or 755 requires specialized training and tools.
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