Fault F07902 occurs when the drive detects that the motor has stalled or is unable to rotate at the commanded speed for a specified period. The drive monitors the relationship between the applied current, the actual speed (or estimated speed in sensorless control), and the torque. If the motor is drawing high current but failing to move—or moving too slowly—the drive triggers F07902 and trips to prevent thermal damage to the motor windings and the inverter. Common Causes of Fault F07902
When F07902 halts your production line, follow this structured troubleshooting methodology to pinpoint and resolve the issue. Step 1: Perform Mechanical Inspections
The threshold speed for stall detection (p2175) or the stall delay time (p2177) may be configured too aggressively for the specific application. 3. Motor and Control Mode Mismatches
The drive was not subjected to static optimization ( p1900=2 ) or rotating measurement during commissioning. siemens drive fault code 7902
The weight or resistance of the process material exceeds the rated torque capability of the motor and drive configuration.
This draft provides a general overview and might need adjustments based on the specific requirements or details of the Siemens drive model you're working with.
When encountering fault code 7902, follow these steps to troubleshoot and potentially resolve the issue: Fault F07902 occurs when the drive detects that
Sometimes the motor is not truly stalled but experiences a heavy load spike (e.g., a crusher hitting a rock). If the delay time ( p2178 ) is set too short, the drive trips before the load can break free.
This is the time the drive waits before tripping. Increase this value slightly if your application experiences high-inertia startups.
When Fault F7902 appears on your Siemens screen, it is usually accompanied by a specific (diagnostic memory integer). This value pinpoints exactly which sub-routine failed during the identification process. Common Causes of Fault F07902 When F07902 halts
The most common cause is a physical obstruction. Debris, seized bearings, product jams in a conveyor, or a misaligned gearbox prevent the rotor from turning. If the drive tries to spin the motor against a locked rotor, it will eventually trip on 7902.
Poor tuning of the sensorless vector control loops. Step-by-Step Troubleshooting Workflow
Check all power cable terminations at both the drive output terminals and the motor terminal box for tightness.