SINAMICS G120 F30002 during ramp-down, what to check?
I'm getting an F30002 fault on my SINAMICS G120 drive, specifically a CU240E-2, whenever the motor ramps down. The drive shuts off with an overvoltage condition in the DC link. What should I check first?
A SINAMICS G120 F30002 fault indicates a DC link overvoltage, meaning the Power Module detected too much voltage and tripped. This often happens during ramp-down, especially with high-inertia loads, due to regenerated energy. Other causes include high line voltage, an interrupted line phase, or an improperly configured DC link voltage controller. The fault value in r0949 shows the DC link voltage at the trip.
Likely causes and checks
1Ramp-down time is too fast for the load's inertia.
- Points to it
- When a high-inertia load decelerates quickly, it regenerates energy back into the drive. If this energy exceeds the drive's capacity to dissipate it, the DC link voltage can rise above the overvoltage threshold, causing an F30002 trip.
- Check
- Increase the ramp-down time (p1121). If operating in U/f mode, also consider setting rounding times (p1130/p1136) to help manage the DC link voltage during rapid deceleration.
2DC link voltage controller is switched off.
- Points to it
- The drive has an internal controller designed to manage DC link voltage, especially during regenerative conditions. If this controller is deactivated (e.g., p1240 or p1280 is set to 0) and no braking resistor is present, the drive cannot effectively prevent overvoltage from regenerated energy.
- Check
- Activate the DC link voltage controller by setting p1240 (for vector control) or p1280 (for U/f control) to an appropriate value.
3DC link voltage controller dynamics are unsuitable.
- Points to it
- Even if the DC link voltage controller is active (indicated by alarm A07400), its dynamic response might not be correctly tuned for the application. This can lead to the controller being unable to effectively manage voltage fluctuations, resulting in an F30002 trip.
- Check
- Adapt the controller dynamics using parameters p1243, p1247 (for vector control), or p1283, p1287 (for U/f control) according to the manufacturer's List Manual.
4Line voltage is too high or p0210 is incorrectly set.
- Points to it
- An excessively high incoming line voltage can directly contribute to an elevated DC link voltage, potentially pushing it over the trip threshold. If the drive's configured supply voltage (p0210) does not match the actual line voltage, the drive's internal calculations for voltage thresholds may be inaccurate.
- Check
- Measure the actual supply voltage and compare it with the value set in p0210 (unit supply voltage). Correct p0210 if there is a discrepancy.
Next check: Given that the fault occurs during ramp-down, the most likely cause is that the ramp-down time (p1121) is too fast for the load's inertia. I would start by increasing p1121 to see if this resolves the issue. If it's a U/f operation, I'd also check p1130/p1136.
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.