Note: If the motor can rotate freely, performing a rotating measurement is often more effective. 5. Finalize Commissioning Set (Quick commissioning for motor parameters). Set p10 = 0 (Return to Operation).
typically corresponds to: "PROFIBUS: Cyclic connection failed" (or PROFINET equivalent, depending on the telegram type)
Once the drive registers that the motor has stalled, it does not shut down immediately. It waits for the duration defined in (Motor Stalled Delay). If the condition persists for that entire period, the drive outputs Fault 7902 and trips.
Always cross-reference physical temperature with sensor reading.
Fault 7902 on a Siemens drive is a "stalled motor" safety trip. By systematically checking the mechanics, verifying motor data, and tuning acceleration parameters, this fault can typically be resolved efficiently. If the fault persists after these steps, the motor may be undersized for the application, or there may be a faulty drive component. siemens drive fault code 7902
Cross-reference the following parameters directly with the physical motor nameplate: Rated motor voltage p0305: Rated motor current p0307: Rated motor power p0311: Rated motor speed
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.
This recalibrates the drive's internal mathematical model of the motor. Prevention and Best Practices
The you are running (Vector control, U/f control, or encoder feedback) Note: If the motor can rotate freely, performing
By systematically verifying the physical wiring, strictly auditing nameplate data entries, and decoding the specific fault value, maintenance professionals can swiftly clear Siemens Fault F7902 and restore stable, optimized operation to their automated systems. To help tailor this to your exact setup, let me know:
The first action is to check the fault value stored in parameter r0949 . This decimal number tells you which detection mechanism triggered the fault:
Marcus, the senior maintenance lead, sighed. He knew this "ghost in the machine" well. F7902 isn't just a number; it’s the Siemens SINAMICS way of saying the motor is stalled The Investigation
Siemens Drive Maintenance / Automation Engineer Date: [Insert current date] Firmware reference: SINAMICS parameter manual, List Manual (LH1) Set p10 = 0 (Return to Operation)
Subject: G120XA solution to warning F7902 motor out of step - Siemens
Does the fault occur or during normal running ?
Check for physical blockages, binding, broken gearboxes, or seized bearings in the driven equipment.
The load is physically stuck, overloaded, or the brake is not releasing.