Siemens SINAMICS G120 Fault Codes: F0001, F0002, F30001

F30001: Power Unit Overcurrent on a G120-2

F30001 means the Power Module detected an overcurrent condition. Siemens assigns an OFF2 reaction, which removes the inverter pulses and allows the motor to coast unless the machine provides another stopping mechanism.

The Siemens CU240B-2/CU240E-2 List Manual identifies the following possible causes:

• Incorrect closed-loop control parameterization
• Motor short circuit or ground fault
• Ramp-up time too short in U/f operation
• Motor rated current much greater than the Power Module rating in U/f operation
• High discharge or recharge current during a line interruption or DC-link dip
• Missing or incorrectly connected line reactor where one is required
• Incorrect power-cable connection
• Motor cable longer than permitted for the configuration
• Defective Power Module
• Interrupted line phase

That list is useful because it prevents a common mistake: assuming every F30001 means failed IGBTs. The Power Module is one possible cause, but the motor circuit, commissioning data, load, supply, and installation must be checked first.

Use r0949 to Narrow Down F30001

On later G120 Control Units, r0949 stores supplementary information for the fault. For F30001, Siemens defines the fault value bitwise:

A value of zero means the drive did not identify a specific overcurrent phase.

Read r0949 before clearing the fault history. A repeated indication on one output phase supports a focused check of that phase’s cable, motor winding, terminal, and power stage. A DC-link indication points the investigation toward supply disturbances, recharge current, or the internal power section.

The fault value is evidence, not a final verdict. It should be considered together with the fault time, operating state, actual current, and what the machine was doing when the trip occurred.

F0001 vs. F30001: Are They the Same Fault?

They describe the same broad fault category, but they are not interchangeable fault records.

The right approach is to identify the installed hardware and use its own List Manual. Do not enter a five-digit code into an old four-digit troubleshooting chart or assume that every legacy remedy applies unchanged to a newer Power Module.

F30002: The Later Equivalent Overvoltage Category

On a later G120-2 system, F30002 indicates Power Module DC-link overvoltage. The usual causes are regenerated motor energy, excessive line voltage, a missing line phase, disabled DC-link voltage control, or unsuitable Vdc controller dynamics.

The first practical adjustment is normally to increase ramp-down time p1121. Siemens also points to rounding times p1130 and p1136, the relevant Vdc controller configuration, line-voltage setting p0210, and line-phase checks.

For F30002, r0949 records the DC-link voltage at the trip in 0.1 V units. That value is particularly useful when deciding whether the problem follows a deceleration event or an unstable/high incoming supply.

Other Related G120 Faults Worth Separating

F30003: DC-Link Undervoltage

Check the line voltage, all supply phases, upstream fuses and contactors, and voltage sag under load. A healthy no-load voltage reading does not rule out a weak connection that collapses when current rises.

F30004: Heat-Sink Overtemperature

Check fan operation, air paths, cabinet temperature, contamination, motor load, and pulse frequency. The fault cannot be successfully acknowledged until the temperature has fallen below the applicable threshold.

F30005: Power Unit I2t Overload

This fault indicates that the Power Module has been overloaded over time, rather than experiencing the instantaneous current event represented by F30001. Review continuous load, duty cycle, drive sizing, motor rating, and current limit p0640.

F30021: Ground Fault

Treat this as an insulation and wiring problem until testing proves otherwise. Disconnect the motor circuit from the Power Module before insulation testing. Check the motor cable, motor winding, cable glands, junction box, brake connection, and grounding system.

F30022: Power Semiconductor Monitoring

This fault can be caused by an output short circuit or a defective semiconductor or gate-supply circuit. It is more likely to require Power Module service, but the output cable and motor must still be isolated and checked before replacement.