Allen-Bradley (Rockwell Automation) PowerFlex 525 fault F005: OverVoltage
Fault F005 on a PowerFlex 525 is OverVoltage: the DC bus voltage exceeded the drive’s maximum value. Rockwell lists high line voltage, line transients and motor regeneration as causes, with longer decel time or a dynamic brake option as the fixes.
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Try Free Drive Diagnostic Upload a keypad photo, the fault history or a parameter export from your Allen-Bradley (Rockwell Automation) PowerFlex 525. InduQT compares the evidence and suggests the next useful checks.
When it happens
- Deceleration or stopping, especially with high-inertia loads
- Running with an overhauling or eccentric load
- Any state, including stopped, if the line voltage is high or has transients
Likely causes and checks
1Decel time too short for the load inertia
- Points to it
- Trips only during stops or speed reductions; F651 shows a high bus voltage at the trip.
- Check
- Lengthen P042 [Decel Time 1] in steps and watch b005 [DC Bus Voltage] on the next stop.
2Bus regulator disabled
- Points to it
- A550 [Bus Reg Enable] = 0 and no braking resistor is fitted.
- Check
- Check A550. Rockwell notes the bus regulator prevents nuisance overvoltage faults but can make actual decel longer than commanded.
3Overhauling or eccentric load
- Points to it
- Trips while running at steady speed on lowering, downhill or cam-type loads.
- Check
- Check whether the load drives the motor; size a dynamic brake resistor per the manual if it does.
4Dynamic brake not working or not enabled
- Points to it
- A resistor is fitted but trips continue.
- Check
- Check A437 [DB Resistor Sel] (when above 0, A550 has no effect), A438 [DB Threshold], and the resistor wiring and value.
5High line voltage or transients
- Points to it
- Trips at constant speed or while stopped; trips coincide with capacitor switching or other supply events.
- Check
- Measure the incoming line voltage and log transients.
Telling it apart
- Trips during decel point to regenerated energy (P042, A550, braking). Trips while stopped or at constant speed point to the supply.
- With the bus regulator on, a drive held at bus limit for one minute gives a stall fault (F006 Motor Stalled) instead of F005, per the manual’s attention note; adjustable with A492 [Stall Fault Time].
- F005 is Type 1. Setting A541 > 0 with A542 = 0 clears it without restarting the drive.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| P042 | [Decel Time 1] | Time to decelerate from P044 [Maximum Freq] to 0 Hz; A443/A445/A447 are the alternate decel times. |
| A550 | [Bus Reg Enable] | Enables the bus regulator (default enabled). Ignored when A437 is above 0. |
| A437 | [DB Resistor Sel] | Enables external dynamic braking and sets resistor protection. |
| A438 | [DB Threshold] | DC bus level at which dynamic braking turns on; see the manual’s warning on resistor wattage. |
Evidence to collect
- b007 and F651 [Fault 1 BusVolts] at the trip
- P042 decel time and P045 stop mode
- A550, A437 and A438 settings
- Whether a brake resistor is fitted, and its value
- Measured line voltage
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