SINAMICS G120 CU240E-2 F30003 during running, what to check?

Question

I'm getting an F30003 fault on a SINAMICS G120 CU240E-2 drive while it's running. This happens intermittently, and I'm trying to figure out the most likely cause.

Top answer · Written by InduQT from the fault guide and manufacturer manuals cited below · Oct 28, 2026

Fault F30003 on a SINAMICS G120 indicates that the Power Module has detected an undervoltage condition in the DC link and has shut down. This can occur during operation if the supply voltage dips or fails, during brownouts, or if a line phase is lost. The undervoltage threshold is dependent on parameter p0210, which defines the unit's supply voltage.

Likely causes and checks

1Supply failure or dip

Points to it: The power supply to the converter may have failed or experienced a significant dip, causing the DC link voltage to drop below the undervoltage threshold.
Check: Compare the fault time (r0948, r2130) with plant power-quality records to see if it correlates with any power events.

2Line voltage below permissible value or p0210 set too high

Points to it: The actual line voltage may be consistently below the minimum permissible value for the drive, or the parameter p0210 (drive unit line supply voltage) might be set incorrectly, making the undervoltage threshold too sensitive.
Check: Measure the line voltage under load and verify that p0210 is set to match the actual supply voltage.

3Line phase interrupted

Points to it: One or more phases of the line supply to the converter may be interrupted, leading to an undervoltage condition in the DC link. This can sometimes be accompanied by an F30011 fault.
Check: With the supply isolated, check the input fuses and connections, then measure all three phases of the line supply.

Next check: After checking for a supply failure or dip, measure the line voltage under load and verify the p0210 setting. If those are correct, isolate the supply and check input fuses and connections, then measure all three phases.

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