Siemens Drive Fault Code 7902 -

If you want to dive deeper into a specific part of this issue, please let me know:

To properly diagnose a 7902 fault, one must understand the following Siemens drive parameters, as they control the sensitivity and detection logic:

However, a critical nuance often missed: In some Siemens drive firmware versions, can also indicate a wire break or short circuit in the temperature sensor feedback circuit , rather than actual overheating. This dual nature makes it a tricky fault to diagnose without systematic testing.

If you are using an encoder, ensure the is correct. If the inverter spins the motor in the opposite direction of the encoder feedback, a 7902 or 7801 fault will occur. siemens drive fault code 7902

Follow this structured approach to identify the source of your F7902 error.

Once your system is running, implement these best practices to prevent recurrence:

| Drive Family | Fault Code | Notes | |--------------|------------|-------| | Sinamics S120 | F07902 | Also logs additional info in r0949 (phase affected: 1=U, 2=V, 3=W) | | Sinamics G120 (CU240E) | F07902 | Can be temporarily inhibited via p2118/p2119 (not recommended for permanent fix) | | Masterdrives (6SE70) | F023 or F024 (older codes) | 7902 appears as “Phase failure output” in newer software versions | | Simotion / Sinamics S150 | F7902 | Same root cause; check also motor holding brake wiring | If you want to dive deeper into a

Manually input the parameters exactly as written on the motor's rating plate: Rated Motor Voltage p305: Rated Motor Current p307: Rated Motor Power p308: Rated Motor CosPhi p311: Rated Motor Speed 4. Optimize the Motor

at start, or only when you add a load? sinamics drive motor fault 7902 - SiePortal - Siemens

Verify the braking relay control voltage. If the brake doesn't receive voltage to release, the motor will stall. 4. Relevant Parameters Motor excitation time (increase if too low) p1745: Fault tolerance p2178: Motor blocked monitoring time p1610: Static torque setpoint p1200: Flying restart 5. Summary Table Suggested Action Fault at startup Perform static/rotating motor ID (p1900=2/3). Fault under load Increase p1610 (torque) or check mechanical load. Fault after power failure Enable flying restart (p1200=1). Motor brake locked Check brake relay and release voltage. To get a more specific solution, tell me: If the inverter spins the motor in the

Siemens drives do not rely solely on external sensors. They use internal at the inverter’s output stage. When the motor is running, the drive expects balanced currents. If one phase deviates by more than a programmable tolerance (typically set via parameter p3230 in Sinamics), the drive triggers fault 7902.

Jams in conveyors, pumps, mixers, or gearboxes physically lock the rotor.

Tell me the exact Siemens drive model (e.g., SINAMICS G120 CU240E-2 ) and whether you have an encoder or are running in V/f or vector control.