What causes Siemens SINAMICS G120 fault F07801?

1. Switching on to a rotating motor: Enable flying restart with p1200. 2. Ramp-up too short or load too high (U/f): Increase p1120 or reduce the load. 3. Current limit or controller settings wrong: Check p0640; in vector control check p1715/p1717; in U/f check p1340–p1346. 4. Motor data or star/delta connection wrong: Check the motor connection and the rating plate data entered in commissioning. 5. Short circuit or ground fault in motor or cable: Disconnect the motor cable at the converter and insulation-test motor and cable.

SINAMICS G120 F07801 Motor Overcurrent: Causes and Checks

Technical review pending. This guide is based on the cited manufacturer documentation; check it against the manual for your exact model and firmware before acting.

Fault F07801 on a SINAMICS G120 means the permissible motor limit current was exceeded. Siemens lists a current limit set too low, an incorrectly set current controller, a too-short ramp-up or too-high load in U/f, a short or ground fault in the motor cable, and switching onto a rotating motor without flying restart.

Diagnose this with AI

Upload a keypad photo, the fault history or a parameter export from your Siemens SINAMICS G120. InduQT compares the evidence and suggests the next useful checks.

Try Free Drive Diagnostic

When it happens

At start, especially onto a still-rotating motor
During acceleration
On a load step

Likely causes and checks

1Switching on to a rotating motor

Points to it: Trips at start on fans or other loads that freewheel; trips stop when the load is stationary.
Check: Enable flying restart with p1200.

2Ramp-up too short or load too high (U/f)

Points to it: Trips partway through acceleration.
Check: Increase p1120 or reduce the load.

3Current limit or controller settings wrong

Points to it: Trips after a parameter change; A07409 (U/f current limiting controller active) appears before the trip.
Check: Check p0640; in vector control check p1715/p1717; in U/f check p1340–p1346.

4Motor data or star/delta connection wrong

Points to it: Trips after a motor or converter change.
Check: Check the motor connection and the rating plate data entered in commissioning.

5Short circuit or ground fault in motor or cable

Points to it: Instant trip regardless of load.
Check: Disconnect the motor cable at the converter and insulation-test motor and cable.

Telling it apart

F07801 is the Control Unit’s motor current limit. F30001 is the Power Module’s hardware overcurrent and F30021 its ground fault.
If the trip only occurs when restarting a coasting load, flying restart (p1200) is the listed remedy, not a longer ramp.

Relevant parameters

Parameter	Name	Why it matters
p0640	Current limit	Siemens’ first check for F07801.
p1120	Ramp-up time	Increase if the trip is during acceleration.
p1200	Flying restart operating mode	Enable when the converter may start onto a rotating motor.
p1340–p1346	U/f current limiting controller	Check in U/f control.

Evidence to collect

r0945/r0949 for F07801
p0640, p1120 and control mode
Whether the motor was turning at the ON command
Motor connection and rating plate
Insulation results

Work on fuel trains, burners, pressure vessels and electrical equipment must be done by qualified personnel following the manufacturer’s documentation and local codes. Never bypass a safety device or interlock.

Siemens SINAMICS G120 fault F07801: Motor overcurrent