Siemens Drive Fault Code 7902 [portable]

In Siemens SINAMICS drives, fault code F07902 indicates a motor stall caused by mechanical overload, incorrect motor data, or improper configuration. Troubleshooting involves verifying motor nameplate data (p304-p311), running identification (p1900=2), and adjusting stall parameters like p2178 to prevent nuisance trips. For detailed troubleshooting steps, visit Siemens Support. sinamics drive motor fault 7902 - SiePortal - Siemens

Siemens drive fault code 7902 (or F07902) indicates that the motor has stalled

. This happens when the drive determines that the motor's actual speed deviates from the setpoint for longer than the configured delay time. Siemens SiePortal Primary Causes and Remedies sinamics drive motor fault 7902 - SiePortal - Siemens

In Siemens SINAMICS drives (such as the G120, S120, or G120XA), fault code F7902 (or F07902) indicates a "Motor Stalled" condition.

This fault occurs when the drive detects that the motor is not rotating properly—or is rotating too slowly—despite being given a command to run. Core Causes

The drive triggers this fault when the deviation between the calculated motor speed and the actual speed exceeds a specific threshold for a set amount of time. sinamics drive motor fault 7902 - SiePortal - Siemens

The Siemens drive fault code 7902 (specifically F07902) indicates that the motor has stalled. This fault occurs when the drive detects that the motor is no longer rotating as expected while under load or during acceleration. Primary Causes

Mechanical Overload: The physical load on the motor is too high, preventing it from reaching the required speed.

Incorrect Motor Data: Motor nameplate parameters (current, power, speed) may be incorrectly entered in the drive configuration.

Missing Identification: Motor data identification and rotating measurements (static optimization) were not performed or completed.

Wiring Issues: Incorrect motor phase lead connections or disconnected motor cables.

Encoder/Sensor Issues: A faulty or incorrectly configured speed sensor/encoder can provide the wrong feedback to the speed controller. Current Limits: The set current limits ( p0640p 0640

) are too low for the application, preventing sufficient torque. Recommended Solutions

According to Siemens Support, you should follow these steps to resolve the fault:

Check Physical Load: Ensure the motor is not physically blocked or overloaded.

Verify Motor Parameters: Double-check the following parameters against the actual motor nameplate: (Rated voltage) (Rated current) (Rated power) (Rated speed) siemens drive fault code 7902

Perform Motor ID: Rerun the motor data identification at standstill by setting

Activate Flying Restart: If the motor fails to stop after an OFF command before being turned back ON, activate the "Flying Restart" function (

Adjust Fault Tolerance: If no mechanical issue is found, you can increase the stall detection delay or tolerance in parameters p1745p 1745 p2178p 2178

For detailed technical guidance, you can consult the official SINAMICS G120 Manual or visit the Siemens SiePortal for community-driven troubleshooting. sinamics drive motor fault 7902 - SiePortal - Siemens

The Siemens drive fault code F07902 indicates a "Motor Stalled" condition. This occurs when the drive detects that the motor speed is significantly below the expected setpoint while it is delivering maximum torque or current. Deep Technical Insight: Why it Occurs

Unlike fault 7900 (Motor Blocked), which usually occurs at very low speeds, F07902 typically triggers when the motor enters a current limit above a specific speed threshold. The drive monitors the deviation between the speed setpoint and the actual speed feedback (or estimated speed in encoderless mode). Primary Causes & Parameters

Mechanical Overload: The most common cause is a physical obstruction or an actual mechanical stall in the driven equipment.

Missing Motor Identification: If the drive hasn't performed a proper "Motor ID" or "Stationary Measurement" (parameter p1900), it may have incorrect data for the motor’s electrical characteristics, leading to false stall detections.

Incorrect Limit Settings: If the current limit (p0640) or torque limits are set too low for the application, the motor cannot pull enough power to move the load, triggering the stall fault.

Flying Restart Issue: In applications where the motor is still spinning when the drive starts (like a fan), a lack of the "Flying Restart" function (p1200) can cause F07902. Troubleshooting Steps

Check Physical Load: Ensure no mechanical binding or seized bearings are preventing rotation.

Verify Parameter p2178: This is the "Motor stalled delay time." Increasing this value can prevent "nuisance" trips during brief heavy load periods.

Adjust Fault Tolerance (p1745): This parameter defines the speed deviation threshold. Increasing it allows for more "slip" before a fault is triggered.

Perform Motor ID: Re-run the motor identification at standstill (p1900 = 2) to ensure the drive has accurate data from the motor's nameplate (p304–p311).

Check Encoder/Direction: Ensure the encoder feedback direction matches the motor rotation direction; an inverted signal will look like a stall to the drive. If you'd like to troubleshoot further, let me know: The exact drive model (e.g., G120, S120, or V90). In Siemens SINAMICS drives, fault code F07902 indicates

Does the fault happen immediately on start or while the machine is running at speed?

Are you using encoder feedback or is it in sensorless (V/f) control? sinamics drive motor fault 7902 - SiePortal - Siemens

Siemens Drive Fault Code 7902: Understanding and Troubleshooting

Siemens drives are widely used in various industrial applications, offering reliable and efficient motor control. However, like any complex device, they can occasionally encounter faults. One such fault code that users may come across is 7902. In this text, we'll explore what the Siemens drive fault code 7902 means, its possible causes, and steps for troubleshooting and resolution.

What is Siemens Drive Fault Code 7902?

Fault code 7902 in Siemens drives typically indicates a specific issue related to the drive's operation. The exact meaning can vary slightly depending on the specific model and version of the Siemens drive. However, generally, this code points to a problem that requires attention to prevent further issues or damage to the drive and connected equipment.

Possible Causes of Fault Code 7902

Several factors can lead to the appearance of fault code 7902 on a Siemens drive:

  1. Overheating: One of the most common reasons, overheating can occur due to high ambient temperatures, inadequate cooling, or excessive load on the drive.
  2. Electrical Issues: Problems such as voltage irregularities, phase loss, or short circuits can trigger this fault code.
  3. Parameter Setting Errors: Incorrect settings or configuration changes can lead to operational faults.
  4. Hardware or Firmware Malfunctions: In some cases, the issue might stem from a hardware failure or a firmware bug.

Troubleshooting Steps

When encountering fault code 7902, follow these steps to troubleshoot and potentially resolve the issue:

  1. Refer to the Drive Manual: The first step is to consult the user manual or documentation specific to your Siemens drive model. Siemens provides detailed descriptions of fault codes, recommended actions, and troubleshooting guides.

  2. Check the Drive’s Environment: Ensure the drive is operating in an environment that meets Siemens’ specified conditions. Check for adequate ventilation and that the ambient temperature is within recommended limits.

  3. Inspect Electrical Connections: Verify that all electrical connections are secure and that there are no signs of damage or wear on cables and connectors.

  4. Review Drive Parameters: Double-check the parameter settings to ensure they are correctly configured for your application.

  5. Reset the Fault: In some cases, simply resetting the fault (if safe to do so) and monitoring the drive can resolve the issue. However, this should be done with caution, as repeated faults can indicate a more serious problem. Overheating: One of the most common reasons, overheating

  6. Contact Siemens Support: If the issue persists, it may be necessary to contact Siemens technical support or a qualified service technician. They can provide guidance specific to your situation and perform repairs if needed.

Preventing Future Occurrences

To minimize the risk of encountering fault code 7902 in the future:

By understanding what Siemens drive fault code 7902 indicates and following systematic troubleshooting steps, users can often quickly resolve issues and maintain the reliability and efficiency of their drive systems.

This draft provides a general overview and might need adjustments based on the specific requirements or details of the Siemens drive model you're working with.

Would you like to add anything specific or make any changes?

Step 5: Advanced Electronics Diagnostics

If the above points pass but the fault persists, suspect drive hardware:

6. Typical Solutions

| Solution | Action | |----------|--------| | Restart communication | Cycle PLC power or reinitialize bus from master | | Correct telegram mismatch | Set same telegram type (e.g., Standard Telegram 1) in both PLC hardware config and P0922 | | Adjust monitoring time | Increase P2040 to 200–500 ms to avoid nuisance trips | | Re-parameterize drive | Load factory defaults (p0010=30, p0970=1) and reconfigure fieldbus settings | | Replace/repair bus cable | Check continuity, shielding, and termination |

Q3: My drive shows F07902 but also F30001 (overcurrent). Which is primary?

Check fault buffer. Often, overcurrent causes rapid heating, which then triggers 7902. Fix the overcurrent first.

Q2: Does fault 7902 lock out the drive?

No. It is a “Trip” fault, not a “Fatal” fault. Once the cause is fixed, acknowledge via terminal, bus, or operator panel.

2. Fault Description

Fault Code 7902 typically corresponds to:
"PROFIBUS: Cyclic connection failed" (or PROFINET equivalent, depending on the telegram type)

In SINAMICS firmware versions (e.g., V4.7+), 7902 indicates that the master-slave cyclic communication has been interrupted or never established. The drive is configured for fieldbus control (e.g., P0700 = 6 for PROFIBUS, or P0922 telegram selected) but no valid cyclic data exchange is occurring.

If Sensor or Wiring Fault:

  1. Replace broken wire: Use twisted, shielded pair for sensor leads. Keep away from power cables.
  2. Correct sensor type in parameters: Align p0600 with actual hardware.
  3. Replace sensor: If resistance check fails (e.g., KTY84 reads <400Ω or >2kΩ at room temp), replace.
  4. Change to motor model without sensor: If sensor unreplaceable (e.g., embedded in motor winding), set p0600 = 0 and use thermal motor model. But ensure p0611 and p0615 are correctly tuned.
  5. Terminal check: On CU310-2, CU320-2, ensure sensor connected to terminals X21.1 and X21.2 (or similar per hardware manual).

Advanced: Changing Fault Response for 7902

In some applications, immediate trip on overtemperature is too aggressive. You can modify the response:

Warning: Delaying trip can destroy motor winding insulation. Only do this if you have secondary protection (e.g., external thermal switch).

Q5: How do I test a KTY84 sensor without removing the motor?

Disconnect drive terminals and measure resistance at room temperature. Should be ~600Ω. Use a hairdryer to warm probe—resistance should increase smoothly.