Motor cables (U, V, W) are connected improperly. Brake Issues: The mechanical brake is not releasing.
Verify U-V-W connections for the motor.
When fault 7902 appears, do not simply reset and restart. Follow this systematic diagnostic sequence. siemens drive fault code 7902
A magnetic contactor between the drive and motor had a pitted auxiliary contact that overheated slightly on the first start of the week, dropping one phase for 50ms. As the day progressed, thermal expansion improved contact – until the next Monday. Motor cables (U, V, W) are connected improperly
Ensure no mechanical binding or seized bearings are preventing rotation. Motor cables (U
For detailed technical guidance, you can consult the official SINAMICS G120 Manual or visit the Siemens SiePortal for community-driven troubleshooting. sinamics drive motor fault 7902 - SiePortal - Siemens