PowerFlex 525 F005 OverVoltage on decel, what to check?
My PowerFlex 525 drive keeps tripping F005 OverVoltage when the machine decelerates. This happens especially with high-inertia loads. What should I check first?
A PowerFlex 525 drive trips F005 (OverVoltage) when the DC bus voltage exceeds its maximum value. This often occurs during deceleration, especially with high-inertia or overhauling loads, or due to high line voltage. The bus regulator function can help prevent nuisance overvoltage faults.
Likely causes and checks
1Deceleration time too short
- Points to it
- The motor is regenerating too much energy back to the drive during deceleration, and the drive's DC bus voltage exceeds its maximum limit because the decel time is too short for the load's inertia.
- Check
- Increase parameter P042 [Decel Time 1] in small increments and monitor b005 [DC Bus Voltage] during the next stop to see if the voltage spike is reduced.
2Bus regulator disabled
- Points to it
- The bus regulator, which helps prevent overvoltage faults during aggressive decelerations or with overhauling loads, might be disabled, allowing the DC bus voltage to rise unchecked.
- Check
- Verify the setting of A550 [Bus Reg Enable]. If it is set to 0 and no dynamic braking resistor is installed, this could be the cause.
3Overhauling or eccentric load
- Points to it
- The load itself is driving the motor, especially in applications like lowering, downhill, or cam-type loads, causing the motor to act as a generator and feed energy back to the drive.
- Check
- Determine if the load is driving the motor. If so, consider sizing and installing a dynamic brake resistor according to the manufacturer's manual.
4Dynamic brake not working or not enabled
- Points to it
- If a dynamic braking resistor is installed, it might not be functioning correctly or is not properly enabled in the drive's parameters, preventing it from dissipating regenerated energy.
- Check
- Check parameters A437 [DB Resistor Sel] (ensure it's above 0), A438 [DB Threshold], and inspect the physical wiring and value of the dynamic braking resistor.
Next check: First, try increasing P042 [Decel Time 1] in small steps and observe the DC bus voltage (b005) during deceleration. If the fault persists, check the status of A550 [Bus Reg Enable].
Related questions
Describe the fault or upload a photo, and InduQT checks it against the manufacturer manuals. Share the result here when it helps someone else.