If using an encoder, incorrect wiring or scaling can cause the drive to think the motor is not moving. Step-by-Step Troubleshooting Guide Follow these steps to diagnose and clear the 7902 fault. Step 1: Check the Mechanical System

: Keep an updated backup of the drive parameters so customized maintenance intervals are not lost during a control unit replacement.

Drive trips during acceleration or while running at low speeds. The motor hums or vibrates but does not spin. Sudden trip upon startup. Causes of Siemens Fault 7902

Mechanically disconnect the motor from the driven equipment. Run the motor uncoupled. If the fault disappears, the problem is a mechanical overload or a seized component in your machine. If the fault persists with the motor uncoupled, the issue lies with the drive, motor, or parameterization.

Fault F07902 indicates that the drive believes the .

In the world of industrial automation, Siemens drives (such as the Sinamics S120, G120, G130, and S150 families) are renowned for their precision, durability, and advanced diagnostic capabilities. However, like any complex electromechanical system, they occasionally encounter faults that can bring production lines to a halt. One such fault that often perplexes maintenance engineers and technicians is .

If the fault occurs exclusively during startup, increase the acceleration ramp time (). A gentler ramp reduces the instantaneous torque demand.

Attempt to rotate the motor shaft manually (if safe and accessible) to ensure the drivetrain moves freely.