Here is a detailed breakdown of the fault, causes, and solutions.
Based on Siemens technical support forums and real-world case studies, the F07902 fault rarely has a single cause. It typically falls into one of the following categories:
If your application uses closed-loop control, a malfunctioning encoder, loose encoder coupling, or damaged feedback cable can report an incorrect speed of 0 RPM to the drive, tricking the firmware into diagnosing a mechanical stall. Step-by-Step Troubleshooting Process siemens drive fault code 7902
The Siemens drive fault code indicates that the drive has detected a stalled motor condition . This critical safety mechanism trips the frequency converter to prevent catastrophic hardware failure, high-current overheating, or mechanical destruction. It primarily appears across the Siemens SINAMICS family, including the G120, G120C, G120XA, and S120 high-performance drives .
To avoid future occurrences of fault code 7902: Here is a detailed breakdown of the fault,
"Power loss," Elias said immediately. "The module has no power. That’s why the main drive is throwing 7902. It’s shouting 'Where are you?' and getting silence."
→ infinite ohms → fault 7902. Short circuit → near 0Ω → fault 7902. To avoid future occurrences of fault code 7902:
This defines the speed below which a stall condition is considered. Lowering this value can prevent premature tripping.
| Parameter | Description | Expected value | |-----------|-------------|----------------| | | Motor temperature (actual) | In °C. If showing -99°C or >250°C, sensor fault is likely. | | p0600 | Temperature sensor type | 0 = none, 1 = KTY84, 2 = PTC, 3 = PT100 | | p0601 | Sensor connection method | 0 = via terminal, 1 = via TM120 module | | p0604 | Overtemperature threshold | Typically 130-160°C for KTY, 90-130°C for PT100 | | p0610 | Motor overtemperature response | Defines reaction (reduce current, trip, etc.) |