F07902: Motor overspeed The actual motor speed has exceeded the p2162 (overspeed threshold) value for longer than the time set in p2163.
In the drive parameters (using STARTER or Startdrive):
| Parameter | Description | Typical Value |
|-----------|-------------|----------------|
| p2040 | Monitoring time for telegrams (ms) | 100–500 ms |
| p0922 | Telegram configuration (e.g., 1, 352, 999) | Match PLC configuration |
| r2060 | Telegram received? | Should increment cyclically |
| p8700 (PROFIBUS) / p8839 (PROFINET) | Station address / device name | Unique and matching PLC | siemens drive fault code 7902
Action:
In the world of industrial automation, Siemens drives (such as the Sinamics S120, G120, G130, and S150 families) are renowned for their precision, durability, and advanced diagnostic capabilities. However, like any complex electromechanical system, they occasionally encounter faults that can bring production lines to a halt. One such fault that often perplexes maintenance engineers and technicians is Siemens drive fault code 7902. F07902: Motor overspeed The actual motor speed has
If you have landed here because your Siemens drive display or your PLC (Programmable Logic Controller) HMI (Human-Machine Interface) is flashing “F07902,” you are likely facing an unexpected downtime scenario. This article provides an exhaustive breakdown of fault code 7902—what it means, why it occurs, and step-by-step methods to troubleshoot and resolve it permanently.
| Root Cause | Solution |
|------------|----------|
| PLC in STOP | Set PLC to RUN or reconfigure drive to ignore missing telegram (p2040 = 0 – not recommended for safety) |
| p2040 too short | Increase p2040 to at least 2–3× bus cycle time |
| Loose connector | Reseat or replace bus connector |
| Wrong telegram type | Match p0922 with PLC configuration (e.g., standard telegram 1 for speed control) |
| No termination | Activate termination on both ends of PROFIBUS segment |
| EMI | Check cable routing, add ferrites, verify shield grounded at both ends |
| Faulty option board | Replace communication board (e.g., CBE20 for PROFINET) | | Root Cause | Solution | |------------|----------| |
Siemens drives do not rely solely on external sensors. They use internal current measurement at the inverter’s output stage. When the motor is running, the drive expects balanced currents. If one phase deviates by more than a programmable tolerance (typically set via parameter p3230 in Sinamics), the drive triggers fault 7902.
This fault is usually latched—meaning the drive will not restart automatically. It requires a manual reset after the root cause is fixed.
F07011 = Motor temperature model warning (pre-trip). F07902 = Trip threshold exceeded.
To effectively troubleshoot, we must split causes into two primary categories: actual overtemperature and sensor/circuit faults.