Set (Identify motor data at standstill) and give a run command to allow the drive to measure winding resistance and leakage inductance. This updates the internal mathematical model for better torque control. Conclusion
: The maintenance interval value was set too low during commissioning, causing premature trips. Steps to Troubleshoot and Resolve the Fault
If the drive detects that the measured values deviate radically from the mathematical model expected based on the entered nameplate parameters, or if the current cannot flow correctly, it aborts the test and throws F7902. siemens drive fault code 7902
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)
The motor is running but cannot match the speed setpoint due to load or tuning. For detailed technical guides, engineers often refer to the Siemens Industry Online Support (SIOS) for a particular drive model like the sinamics drive motor fault 7902 - SiePortal - Siemens Set (Identify motor data at standstill) and give
If the application requires it, activate flying restart by setting . 6. Perform a Motor ID Run
Elias shook his head. "It’s an S120 multi-drive system, Marcus. Look at the cabinet. One line supply module, but two motor modules. There’s a main drive for the flywheel, and a secondary servo for the feeder that pushes the metal sheets in. They talk to each other via a telegram to synchronize the speed. If the feeder drive doesn't report its position to the main drive, the main drive locks out to prevent crushing the tooling." Steps to Troubleshoot and Resolve the Fault If
7902 Typical device family: Siemens SINAMICS / SIMODRIVE (frequency converters and servo drives) Symptom: Drive reports fault 7902 and trips or blocks operation. Likely meaning: Encoder feedback error or position feedback failure detected by the drive's encoder interface. The drive cannot reliably determine motor position/speed. Common causes:
Update the corresponding drive parameter to accurately reflect this topology. 3. Inspect the Physical Motor and Cable Integrity
In closed-loop control modes, a damaged encoder, loose coupling, or broken feedback cable will feed incorrect speed data back to the inverter.
Understanding what causes the stall detection to trip will help narrow down your physical and software-based checks.