Siemens Drive Fault Code 7902

Program longer acceleration ramps ( p1120 ) for heavy loads to allow torque to build up gradually. If you need help adjusting these settings, let me know: The exact Siemens drive model (e.g., G120, S120) Whether you use an encoder or run in sensorless control The type of mechanical load connected to the motor Share public link

Before typing in numbers, ensure parameter p0300 (Motor Type) is precisely set (e.g., 1 for induction motor, 2 for synchronous motor). This changes the drive's underlying internal algorithms.

Elias Thorne, a third-shift maintenance technician with twenty years of grease under his fingernails, sat in the breakroom nursing a lukewarm coffee. He was staring at the clock. It was 2:00 AM. In the world of industrial automation, 2:00 AM is the witching hour—the time when bearings decide to seize, sensors decide to sleep, and PLC logic decides to glitch.

Access the drive parameters using your commissioning tool (TIA Portal, Startdrive, or STARTER) or the Operator Panel (BOP-2 / IOP-2).

This parameter defines the speed deviation threshold. Increasing it allows for more "slip" before a fault is triggered. siemens drive fault code 7902

Siemens Drive Fault Code 7902 is a sophisticated safety feature designed to protect machinery from damage due to unexpected stops. While the initial appearance of the fault may suggest a major mechanical seizure, the root cause is often a simple fix: a stuck brake, a misconfigured encoder, or a delay time set too strictly.

Tighten all terminal connections at both the inverter output and the motor terminal box.

| Cause | Explanation | |-------|-------------| | | Motor is consistently operating above its rated torque or current (e.g., conveyor jam, heavy cutting load). | | Insufficient cooling | Blocked cooling fins, failed external fan, or dusty environment reducing heat dissipation. | | High ambient temperature | Motor located near ovens, furnaces, or in non-ventilated enclosures. | | Low speed operation with self-cooling motor | Motors relying on shaft-mounted fans lose cooling at low RPMs but may still draw high current. | | Pulse frequency too high | Higher switching losses in motor iron core generate extra heat; parameter p1800 may be set above recommended value. | | Incorrect motor parameters | Wrong rated current or thermal time constant (p0305, p0611) leads to miscalculated temperature model. |

"Power loss," Elias said immediately. "The module has no power. That’s why the main drive is throwing 7902. It’s shouting 'Where are you?' and getting silence." Program longer acceleration ramps ( p1120 ) for

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.

This is a diagnostic and troubleshooting report for .

The you are running (Vector control, U/f control, or encoder feedback)

Once physical maintenance is complete, reset the internal counter to clear the 7902 code and start a new cycle: In the world of industrial automation, 2:00 AM

This comprehensive troubleshooting guide breaks down the core internal logic, primary physical causes, parameter mitigation strategies, and sequential resolutions for the F07902 fault code. Internal Diagnostic Logic: Why F07902 Triggers

The actual motor speed has exceeded the p2162 (overspeed threshold) value for longer than the time set in p2163 .

| Parameter | Description | Expected value | |-----------|-------------|----------------| | | Motor temperature (actual) | In °C. If showing -99°C or >250°C, sensor fault is likely. | | p0600 | Temperature sensor type | 0 = none, 1 = KTY84, 2 = PTC, 3 = PT100 | | p0601 | Sensor connection method | 0 = via terminal, 1 = via TM120 module | | p0604 | Overtemperature threshold | Typically 130-160°C for KTY, 90-130°C for PT100 | | p0610 | Motor overtemperature response | Defines reaction (reduce current, trip, etc.) |