Siemens Drive Fault Code 7902 is a sophisticated safety feature designed to protect machinery from damage due to unexpected stops. While the initial appearance of the fault may suggest a major mechanical seizure, the root cause is often a simple fix: a stuck brake, a misconfigured encoder, or a delay time set too strictly.
Re-run the motor identification at standstill ( p1900 = 2 ) to ensure the drive has accurate data from the motor's nameplate (p304–p311). siemens drive fault code 7902
Lower this value if the drive trips too early during slow-speed operations. Siemens Drive Fault Code 7902 is a sophisticated
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 Lower this value if the drive trips too
If the motor spins but the drive still reports a 7902 fault, the PI controller may be too slow to respond, allowing the motor to lag behind the setpoint.
Check fault buffer. Often, overcurrent causes rapid heating, which then triggers 7902. Fix the overcurrent first.
Configure pre-alarm thresholds in the Siemens drive (such as configuring an output relay or PLC alarm bit for "Current Limit Reached") to warn operators of an impending overload condition before the stall timer reaches zero.