What is f7902 fault in g120?

If your Sinamics G120 drive is staring back at you with a F7902 code, it’s essentially telling you: "I tried to spin the motor, but it’s not moving (or not moving the way I expected)."

In technical terms, F7902 is a Motor Stalled fault. This happens when the drive detects that the motor has been at the current limit for longer than the "stall duration" set in the parameters.

Here is a breakdown of why this happens and how to fix it.

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🔍 Common Causes

The drive triggers this fault when the actual speed deviates too far from the setpoint while the current is maxed out.

• Mechanical Overload: The load is simply too heavy or the machinery is jammed.

• Ramp Times: The acceleration time (P1120) is too short for the inertia of the load.

• Incorrect Motor Data: The drive doesn't "know" the motor well enough (incorrect P0300 series parameters).

• Current Limits: The torque or current limits are set too low (P0640).

• Loss of Phase: A break in the motor cable or a loose connection.

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🛠️ Troubleshooting & Solutions

Step	Action	Details
1	Check Mechanics	Rotate the motor shaft manually (if safe). Check for seized bearings or jammed gearboxes.
2	Verify Parameters	Ensure the motor Nameplate Data (P0304–P0311) matches the physical motor.
3	Increase Ramp Time	If it trips during startup, increase P1120 (Acceleration Time).
4	Check Stall Settings	Review P2175 (Stall speed threshold) and P2177 (Delay time). You may need to increase the delay if your application has high momentary loads.
5	Motor ID Run	Perform a "Motor Data Identification" (P1900 = 2). This helps the drive map the motor's electrical characteristics perfectly.