Drive Fault Code 7902 Exclusive: Siemens

If the drive is in closed-loop control (p1300 = 21) and the encoder signal is faulty, the drive may get conflicting data.

Siemens Drive Fault Code 7902: Comprehensive Troubleshooting Guide

If the motor data identification (p1910 / p1960) was not performed, the internal motor model may be inaccurate. The drive might calculate a speed that does not match reality, leading to a false positive stall alarm. This is especially common when commissioning third-party motors without performing a rotating measurement.

Diagnosis requires looking at the hardware, the application, and the software parameters:

Unlike a standard overload alarm, which trips due to high current, 7902 indicates a mismatch between the commanded speed and the actual mechanical movement. The drive is effectively telling the controller: "I am sending energy to the motor to turn, but the shaft is not moving as expected." siemens drive fault code 7902

If you see , your drive has been "orphaned." It thinks the controller (PLC) has abandoned it. 95% of the time, this is a broken cable, a loose connector, or the PLC being stopped.

Cross-reference the drive parameters directly against the physical metal nameplate stamped on the motor chassis. Verify the following critical values: Rated Motor Current (p0305) Rated Motor Power (p0307) Rated Motor Frequency (p0310) Rated Motor Speed (p0311)

Siemens drives monitor two distinct types of rotation failures:

This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. If the drive is in closed-loop control (p1300

In industrial automation, unexpected drive downtime cuts directly into production profitability. If your Siemens SINAMICS drive system—such as the widely used G120, S120, or G120C series—suddenly trips and displays , the drive has triggered a "Motor stalled" protective action.

Understanding why this fault occurs, how to diagnose it safely, and the steps required to resolve it ensures minimal downtime and maintains the operational longevity of your machinery. What is Siemens Fault Code F07902?

While the core logic of F7902 is consistent, specific product lines have unique considerations:

Lock out and tag out (LOTO) the drive following local safety protocols. 95% of the time, this is a broken

Check the mechanical coupling of the encoder to the motor shaft to ensure it is not slipping. Step 5: Evaluate Low-Speed Control Modes

Give the drive a run command to allow it to measure winding resistance and leakage inductance.

Verify that all electrical connections are secure and that there are no signs of damage or wear on cables and connectors.