The Siemens drive fault code 7902 (often displayed as F07902 or A07902 depending on the drive series) typically indicates a motor overspeed condition.
Here is the breakdown and common solutions for this fault.
| Step | Action | |------|--------| | 1 | Check r0063 (actual speed) — does it really exceed p2162? | | 2 | Verify p1082 (maximum speed) ≥ p2162 (overspeed threshold). | | 3 | Increase p2162 slightly (e.g., 1.1× p1082) if mechanical limits allow. | | 4 | Check encoder: cable shielding, terminal tightness, p0400 encoder type. | | 5 | Perform motor data identification (p1910 = 1) and speed controller optimization (p1960 = 1). | | 6 | Increase deceleration time p1121 to avoid regen overshoot. |
If the above points pass but the fault persists, suspect drive hardware:
Follow this systematic approach. Always lock out and tag out power before touching terminals.
Use an infrared thermometer or thermal imager for accuracy.
For PROFIBUS:
For PROFINET:
Siemens drive fault code 7902 is unequivocally a power delivery warning. In 95% of cases, the problem is external to the drive: a loose wire, a failing contactor, a damaged cable, or a motor winding opening. Only in about 5% of cases is the drive’s own output stage at fault.
By following a logical, step-by-step diagnostic process—visual inspection, continuity testing, megger testing, and swap tests—you can pinpoint the cause within an hour. Remember: do not simply reset the fault and restart. Find the physical root cause, or it will return, often with more severe damage (including a burnt motor or drive).
Lastly, document your findings. Keeping a log of recurring 7902 faults can reveal systemic issues like undersized cables, excessive vibration, or environmental contamination (dust, moisture) in the motor terminal box.
Need further assistance? Consult the official Siemens manual for your specific drive model (function diagrams 8010–8020 for output monitoring). For hands-on help, Siemens Technical Support can provide remote diagnostic assistance using Starter or STARTER software to trace current waveforms in real time.
Keywords: Siemens drive fault 7902, F07902 Sinamics, phase failure in motor cable, Siemens drive troubleshooting, motor phase loss detection.
The fluorescent lights of the MagnaDrive factory floor hummed in a low, monotonous key, a sound usually drowned out by the rhythmic thwump-hiss-thwump of the heavy-duty stamping presses. But tonight, the factory was holding its breath.
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.
As if on cue, the breakroom lights flickered. The deep, vibrating thrum of the plant’s ventilation system shuddered and died. A moment later, the emergency lights kicked in, bathing the hallway in an eerie, sterile red.
Elias’s radio crackled to life. It was the shift supervisor, Marcus, his voice tight with panic.
"Elias. Line 4. Main stamper. It’s down. Totally dead. The screen is screaming at me."
Elias sighed, pushing himself out of the chair. "I'm on my way. Don't touch anything, Marcus."
Line 4 was the heart of the factory, a massive Siemens-driven servo press responsible for churning out the chassis plates for the new electric vehicle contract. If it was down, the morning shift would start with a disaster, and the plant manager would be breathing down everyone's necks before sunrise.
When Elias arrived, the massive machine stood silent, a sleeping giant. The control cabinet door was open, and Marcus was standing back, looking at the Siemens Sinamics S120 drive module like it was a bomb about to detonate.
"What’s the code, Marcus?" Elias asked, pulling his laptop bag onto a nearby workbench.
"It’s a 7902," Marcus said, reading the 7-segment display on the BOP (Basic Operator Panel). "Just '7902'. I tried resetting it, but it just clicks and throws the same code again."
Elias stopped. He pulled off his safety glasses and wiped the sweat from his forehead. He knew this code. Every drive tech knows the "standard" faults—overvoltage (F0002), overcurrent (F0001)—but the 7-series faults were different. They were communication faults. Ghosts in the machine.
"Fault 7902," Elias muttered, typing his password into the Siemens TIA Portal software on his laptop. "Communication fault. Drive-to-Drive data exchange failure."
"That doesn't make sense," Marcus snapped. "We didn't change anything. It was running fine at 1:45, and then—bang—e-stop tripped, and this code popped up."
Elias connected the Profinet cable to the drive’s CU320-2 control unit. The laptop chimed. He navigated to the diagnostics buffer. The list was populated, but one entry was highlighted in red, pulsating with urgency. siemens drive fault code 7902
F07902: Drive-to-drive communication failure.
"It’s not the PLC," Elias murmured, scrolling through the parameters. "The PLC is talking to the drive just fine. The Profibus light is green. This fault... it means this drive isn't hearing its partner."
"Partner?" Marcus asked. "The press only has one main motor."
Elias shook his head. "It’s an S120 multi-drive system, Marcus. Look at the cabinet. One line supply module, but two motor modules. There’s a main drive for the flywheel, and a secondary servo for the feeder that pushes the metal sheets in. They talk to each other via a telegram to synchronize the speed. If the feeder drive doesn't report its position to the main drive, the main drive locks out to prevent crushing the tooling."
Marcus looked at the row of black modules in the cabinet. "Okay, so we check the second drive."
They moved to the lower section of the cabinet. The lights on the second motor module were dark. Completely dark.
"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."
The diagnosis seemed simple, but Elias knew better. If it was just a loose wire, the breaker would have tripped. He pulled out his multimeter.
"Breaker is on," he muttered. "Voltage at the input terminals... 480 volts, phase to phase. The power is there."
He checked the DC link voltage. The capacitors in the line module were humming, charged and ready. But the second motor
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).
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
The Siemens drive fault code indicates that motor has stalled or is out of step
. This typically occurs when the drive loses synchronism with the motor, meaning the motor is unable to rotate at the speed commanded by the inverter. Common Causes Missing Motor Data Identification
: The most frequent cause is a lack of motor data identification and static optimization, particularly with asynchronous motors. Mechanical Overload The Siemens drive fault code 7902 (often displayed
: The load on the motor exceeds its torque capability, physically preventing it from turning. Incorrect Parameter Settings
: Limits for stall detection (such as speed or current thresholds) may be set too strictly for the specific application. Acceleration/Deceleration Rates
: Ramp times that are too aggressive (too short) can cause the drive to lose control of the motor rotor position. Recommended Troubleshooting Steps Perform Motor Identification
: Re-run the motor data identification routine (often called "MotID") to ensure the drive accurately understands the electrical characteristics of the motor. Check Mechanical Load
: Inspect the connected machinery for jams, broken bearings, or excessive friction that could be stalling the shaft. Adjust Stall Protection Parameters
: Verify and potentially increase the stall detection time or torque limits if the application involves high-inertia loads. Review Ramp Times
: Increase the acceleration (P1120) and deceleration (P1121) times to allow the motor more time to reach the setpoint without losing synchronism. Verify Power Supply
: Ensure the input voltage is stable, as a significant voltage drop can reduce the motor's available torque.
For detailed parameter lists and specific drive models, you can refer to the Siemens SiePortal Support F7902 Technical FAQ specific parameter numbers for a particular Siemens drive series, such as the SINAMICS G120
Subject: G120XA solution to warning F7902 motor out of step - Siemens
In industrial automation, encountering a Siemens Drive Fault Code 7902—specifically F07902: Motor Stalled—can bring production to a grinding halt. This fault is common across various Siemens Sinamics series, including the G120, S120, and G120XA models. Understanding what this code means and how to systematically troubleshoot it is essential for minimizing downtime. What is Siemens Fault 7902?
Fault F07902 indicates that the drive has detected a motor stall. This occurs when the actual speed of the motor deviates from the speed setpoint by more than a specified threshold for a set period.
While related to F07900 (Motor Blocked), F07902 typically triggers at higher speeds or under specific torque conditions where the drive is attempting to move the motor, but the feedback or calculated model indicates it is not following the command. Common Causes of Fault 7902 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)
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 Use an oscilloscope on the drive’s output (with
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
Mechanical Stall: The load is too heavy, the machine is jammed, or the motor is physically unable to move.
Incorrect Motor Data: The drive's parameters do not match the physical motor plate (incorrect
Missing Identification/Optimization: Motor data identification (motor tuning) has not been performed, or the static/rotating measurements were not completed successfully.
Incorrect Connections: Motor cables (U, V, W) are connected improperly, or the encoder signal is reversed (if applicable). Premature Startup: Motor excitation time ( p0346p 0346
) is too short, leading to starting before the field is established. Recommended Troubleshooting Steps
Check Mechanical Load: Ensure the motor is not physically obstructed and the brake (if any) is fully releasing. Verify Motor Nameplate Data: Re-enter motor data ( p0304p 0304 rated voltage, p0305p 0305 p0307p 0307 p0308p 0308 p0311p 0311 rated speed) precisely.
Perform Motor Identification (ID): Run the static/rotating motor data identification (set and start the drive).
Check Cable Connections: Verify U-V-W connections for the motor.
Adjust Fault Tolerance: If the motor isn't genuinely stalling but the drive thinks it is, you can adjust parameters to be less sensitive: Increase delay time: p2178p 2178 (Stall delay). Increase fault tolerance: p1745p 1745 . Specific Fix for G120XA
If the fault occurs on a SINAMICS G120XA, follow this Siemens recommended procedure: Reset the converter to factory settings. Set (V/f) or (Vector). Enter motor nameplate data ( p0304p 0304 p0311p 0311 Set (Quick commission). Set (Ident. at standstill). Start the motor in Hand mode to run the motor ID. Critical Parameters to Review p0346p 0346
: Motor excitation time (increase if fault occurs immediately at start). p1610p 1610
: Acceleration torque (increase to provide more starting torque). r0949r 0949 : Fault value (interprets the exact cause of the stall). To help narrow down the solution, could you tell me:
What is the specific model of your Siemens drive (e.g., G120, G120XA, S120)?
Is this a new installation or has it been running fine before?
Does the fault happen immediately at start, or only when you add a load? 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
Understanding and Resolving Siemens Drive Fault Code 7902 The Siemens Drive Fault Code 7902 (often displayed as F07902) is a critical error indicating a "Motor Stalled" condition. This fault occurs when the drive’s control logic determines that the motor is not rotating as expected despite receiving power, or when the deviation between the calculated motor speed and the actual measured speed exceeds defined limits.
While this fault is common across various series including SINAMICS S120, G120, G120XA, and G115D, its root causes can range from simple mechanical blockages to complex parameterization errors. Primary Causes of Fault 7902
Understanding why the drive triggers a stall fault is the first step in troubleshooting. Common triggers include: SINAMICS G120XA fault F07902 - ID: 109773411 - Support
This is a diagnostic and troubleshooting report for Siemens Drive Fault Code 7902.
To avoid future occurrences of fault code 7902:
F07011 = Motor temperature model warning (pre-trip). F07902 = Trip threshold exceeded.
The Siemens drive fault code 7902 (often displayed as F07902 or A07902 depending on the drive series) typically indicates a motor overspeed condition.
Here is the breakdown and common solutions for this fault.
| Step | Action | |------|--------| | 1 | Check r0063 (actual speed) — does it really exceed p2162? | | 2 | Verify p1082 (maximum speed) ≥ p2162 (overspeed threshold). | | 3 | Increase p2162 slightly (e.g., 1.1× p1082) if mechanical limits allow. | | 4 | Check encoder: cable shielding, terminal tightness, p0400 encoder type. | | 5 | Perform motor data identification (p1910 = 1) and speed controller optimization (p1960 = 1). | | 6 | Increase deceleration time p1121 to avoid regen overshoot. |
If the above points pass but the fault persists, suspect drive hardware:
Follow this systematic approach. Always lock out and tag out power before touching terminals.
Use an infrared thermometer or thermal imager for accuracy.
For PROFIBUS:
For PROFINET:
Siemens drive fault code 7902 is unequivocally a power delivery warning. In 95% of cases, the problem is external to the drive: a loose wire, a failing contactor, a damaged cable, or a motor winding opening. Only in about 5% of cases is the drive’s own output stage at fault.
By following a logical, step-by-step diagnostic process—visual inspection, continuity testing, megger testing, and swap tests—you can pinpoint the cause within an hour. Remember: do not simply reset the fault and restart. Find the physical root cause, or it will return, often with more severe damage (including a burnt motor or drive).
Lastly, document your findings. Keeping a log of recurring 7902 faults can reveal systemic issues like undersized cables, excessive vibration, or environmental contamination (dust, moisture) in the motor terminal box.
Need further assistance? Consult the official Siemens manual for your specific drive model (function diagrams 8010–8020 for output monitoring). For hands-on help, Siemens Technical Support can provide remote diagnostic assistance using Starter or STARTER software to trace current waveforms in real time.
Keywords: Siemens drive fault 7902, F07902 Sinamics, phase failure in motor cable, Siemens drive troubleshooting, motor phase loss detection.
The fluorescent lights of the MagnaDrive factory floor hummed in a low, monotonous key, a sound usually drowned out by the rhythmic thwump-hiss-thwump of the heavy-duty stamping presses. But tonight, the factory was holding its breath.
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.
As if on cue, the breakroom lights flickered. The deep, vibrating thrum of the plant’s ventilation system shuddered and died. A moment later, the emergency lights kicked in, bathing the hallway in an eerie, sterile red.
Elias’s radio crackled to life. It was the shift supervisor, Marcus, his voice tight with panic.
"Elias. Line 4. Main stamper. It’s down. Totally dead. The screen is screaming at me."
Elias sighed, pushing himself out of the chair. "I'm on my way. Don't touch anything, Marcus."
Line 4 was the heart of the factory, a massive Siemens-driven servo press responsible for churning out the chassis plates for the new electric vehicle contract. If it was down, the morning shift would start with a disaster, and the plant manager would be breathing down everyone's necks before sunrise.
When Elias arrived, the massive machine stood silent, a sleeping giant. The control cabinet door was open, and Marcus was standing back, looking at the Siemens Sinamics S120 drive module like it was a bomb about to detonate.
"What’s the code, Marcus?" Elias asked, pulling his laptop bag onto a nearby workbench.
"It’s a 7902," Marcus said, reading the 7-segment display on the BOP (Basic Operator Panel). "Just '7902'. I tried resetting it, but it just clicks and throws the same code again."
Elias stopped. He pulled off his safety glasses and wiped the sweat from his forehead. He knew this code. Every drive tech knows the "standard" faults—overvoltage (F0002), overcurrent (F0001)—but the 7-series faults were different. They were communication faults. Ghosts in the machine.
"Fault 7902," Elias muttered, typing his password into the Siemens TIA Portal software on his laptop. "Communication fault. Drive-to-Drive data exchange failure."
"That doesn't make sense," Marcus snapped. "We didn't change anything. It was running fine at 1:45, and then—bang—e-stop tripped, and this code popped up."
Elias connected the Profinet cable to the drive’s CU320-2 control unit. The laptop chimed. He navigated to the diagnostics buffer. The list was populated, but one entry was highlighted in red, pulsating with urgency.
F07902: Drive-to-drive communication failure.
"It’s not the PLC," Elias murmured, scrolling through the parameters. "The PLC is talking to the drive just fine. The Profibus light is green. This fault... it means this drive isn't hearing its partner."
"Partner?" Marcus asked. "The press only has one main motor."
Elias shook his head. "It’s an S120 multi-drive system, Marcus. Look at the cabinet. One line supply module, but two motor modules. There’s a main drive for the flywheel, and a secondary servo for the feeder that pushes the metal sheets in. They talk to each other via a telegram to synchronize the speed. If the feeder drive doesn't report its position to the main drive, the main drive locks out to prevent crushing the tooling."
Marcus looked at the row of black modules in the cabinet. "Okay, so we check the second drive."
They moved to the lower section of the cabinet. The lights on the second motor module were dark. Completely dark.
"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."
The diagnosis seemed simple, but Elias knew better. If it was just a loose wire, the breaker would have tripped. He pulled out his multimeter.
"Breaker is on," he muttered. "Voltage at the input terminals... 480 volts, phase to phase. The power is there."
He checked the DC link voltage. The capacitors in the line module were humming, charged and ready. But the second motor
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).
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
The Siemens drive fault code indicates that motor has stalled or is out of step
. This typically occurs when the drive loses synchronism with the motor, meaning the motor is unable to rotate at the speed commanded by the inverter. Common Causes Missing Motor Data Identification
: The most frequent cause is a lack of motor data identification and static optimization, particularly with asynchronous motors. Mechanical Overload
: The load on the motor exceeds its torque capability, physically preventing it from turning. Incorrect Parameter Settings
: Limits for stall detection (such as speed or current thresholds) may be set too strictly for the specific application. Acceleration/Deceleration Rates
: Ramp times that are too aggressive (too short) can cause the drive to lose control of the motor rotor position. Recommended Troubleshooting Steps Perform Motor Identification
: Re-run the motor data identification routine (often called "MotID") to ensure the drive accurately understands the electrical characteristics of the motor. Check Mechanical Load
: Inspect the connected machinery for jams, broken bearings, or excessive friction that could be stalling the shaft. Adjust Stall Protection Parameters
: Verify and potentially increase the stall detection time or torque limits if the application involves high-inertia loads. Review Ramp Times
: Increase the acceleration (P1120) and deceleration (P1121) times to allow the motor more time to reach the setpoint without losing synchronism. Verify Power Supply
: Ensure the input voltage is stable, as a significant voltage drop can reduce the motor's available torque.
For detailed parameter lists and specific drive models, you can refer to the Siemens SiePortal Support F7902 Technical FAQ specific parameter numbers for a particular Siemens drive series, such as the SINAMICS G120
Subject: G120XA solution to warning F7902 motor out of step - Siemens
In industrial automation, encountering a Siemens Drive Fault Code 7902—specifically F07902: Motor Stalled—can bring production to a grinding halt. This fault is common across various Siemens Sinamics series, including the G120, S120, and G120XA models. Understanding what this code means and how to systematically troubleshoot it is essential for minimizing downtime. What is Siemens Fault 7902?
Fault F07902 indicates that the drive has detected a motor stall. This occurs when the actual speed of the motor deviates from the speed setpoint by more than a specified threshold for a set period.
While related to F07900 (Motor Blocked), F07902 typically triggers at higher speeds or under specific torque conditions where the drive is attempting to move the motor, but the feedback or calculated model indicates it is not following the command. Common Causes of Fault 7902 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)
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
Mechanical Stall: The load is too heavy, the machine is jammed, or the motor is physically unable to move.
Incorrect Motor Data: The drive's parameters do not match the physical motor plate (incorrect
Missing Identification/Optimization: Motor data identification (motor tuning) has not been performed, or the static/rotating measurements were not completed successfully.
Incorrect Connections: Motor cables (U, V, W) are connected improperly, or the encoder signal is reversed (if applicable). Premature Startup: Motor excitation time ( p0346p 0346
) is too short, leading to starting before the field is established. Recommended Troubleshooting Steps
Check Mechanical Load: Ensure the motor is not physically obstructed and the brake (if any) is fully releasing. Verify Motor Nameplate Data: Re-enter motor data ( p0304p 0304 rated voltage, p0305p 0305 p0307p 0307 p0308p 0308 p0311p 0311 rated speed) precisely.
Perform Motor Identification (ID): Run the static/rotating motor data identification (set and start the drive).
Check Cable Connections: Verify U-V-W connections for the motor.
Adjust Fault Tolerance: If the motor isn't genuinely stalling but the drive thinks it is, you can adjust parameters to be less sensitive: Increase delay time: p2178p 2178 (Stall delay). Increase fault tolerance: p1745p 1745 . Specific Fix for G120XA
If the fault occurs on a SINAMICS G120XA, follow this Siemens recommended procedure: Reset the converter to factory settings. Set (V/f) or (Vector). Enter motor nameplate data ( p0304p 0304 p0311p 0311 Set (Quick commission). Set (Ident. at standstill). Start the motor in Hand mode to run the motor ID. Critical Parameters to Review p0346p 0346
: Motor excitation time (increase if fault occurs immediately at start). p1610p 1610
: Acceleration torque (increase to provide more starting torque). r0949r 0949 : Fault value (interprets the exact cause of the stall). To help narrow down the solution, could you tell me:
What is the specific model of your Siemens drive (e.g., G120, G120XA, S120)?
Is this a new installation or has it been running fine before?
Does the fault happen immediately at start, or only when you add a load? 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
Understanding and Resolving Siemens Drive Fault Code 7902 The Siemens Drive Fault Code 7902 (often displayed as F07902) is a critical error indicating a "Motor Stalled" condition. This fault occurs when the drive’s control logic determines that the motor is not rotating as expected despite receiving power, or when the deviation between the calculated motor speed and the actual measured speed exceeds defined limits.
While this fault is common across various series including SINAMICS S120, G120, G120XA, and G115D, its root causes can range from simple mechanical blockages to complex parameterization errors. Primary Causes of Fault 7902
Understanding why the drive triggers a stall fault is the first step in troubleshooting. Common triggers include: SINAMICS G120XA fault F07902 - ID: 109773411 - Support
This is a diagnostic and troubleshooting report for Siemens Drive Fault Code 7902.
To avoid future occurrences of fault code 7902:
F07011 = Motor temperature model warning (pre-trip). F07902 = Trip threshold exceeded.