Siemens Drive Fault Code 7902 |best| -
| Step | Action | |------|--------| | 1 | Check (actual speed) — does it really exceed p2162? | | 2 | Verify p1082 (maximum speed) ≥ p2162 (overspeed threshold). | | 3 | Increase p2162 slightly (e.g., 1.1× p1082) if mechanical limits allow. | | 4 | Check encoder: cable shielding, terminal tightness, p0400 encoder type. | | 5 | Perform motor data identification (p1910 = 1) and speed controller optimization (p1960 = 1). | | 6 | Increase deceleration time p1121 to avoid regen overshoot. |
Check all power cable terminations at both the drive output terminals and the motor terminal box for tightness.
: If the motor's actual speed deviates from the setpoint and falls outside this window, the SAC ramps up its output to compensate. If the output remains outside the bounds for longer than the delay time configured in parameter p2178 , the drive trips on F07902 . F07900 (Motor Blocked) vs. F07902 (Motor Stalled) siemens drive fault code 7902
If the deviation between the actual speed and the expected setpoint breaks the default stall window threshold—and remains there longer than the stall delay time configured in parameter —the processor determines the rotor is no longer keeping pace with the magnetic field. The drive trips on F07902 to protect the winding insulation from thermal destruction. Key Parameter Impact on Fault 7902 p2178 Motor stalled delay time
Regularly lubricate bearings and check conveyor/gearbox alignments to minimize parasitic friction. | Step | Action | |------|--------| | 1
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If using an encoder, monitor the actual speed value ( r0061 or r0063 ) against the setpoint speed during the brief moments before the drive trips. If the motor is physically spinning but the drive reads 0 RPM, check the encoder wiring, power supply, and shielding. Step 5: Run Motor Identification (ID) | | 4 | Check encoder: cable shielding,
The root causes generally fall into four primary categories:
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 .
Check the continuity of the motor cables between the drive output terminals and the motor terminal box.
If you want, I can draft a troubleshooting checklist tailored to a specific Siemens drive model (e.g., SINAMICS G120, S120, or SIMODRIVE) — tell me the exact model and motor/encoder type.
