F07902: Motor overspeed The actual motor speed has exceeded the p2162 (overspeed threshold) value for longer than the time set in p2163.
Scenario: A automotive paint line conveyor trips with F07902 every Monday morning but runs fine for the rest of the week.
Investigation: Technicians found no cable breaks. The motor windings tested OK. The clue was the timing – every Monday after weekend shutdown.
Root Cause: A magnetic contactor between the drive and motor had a pitted auxiliary contact that overheated slightly on the first start of the week, dropping one phase for 50ms. As the day progressed, thermal expansion improved contact – until the next Monday.
Solution: Replaced contactor and implemented weekly starter torque check. Fault 7902 eliminated.
For PROFIBUS:
For PROFINET:
Begin with verifying that the PLC master is actively exchanging cyclic data with the drive’s configured station address. Then check hardware integrity of the bus cable and termination. If the issue persists, match telegram settings exactly between the drive (P0922) and the master’s hardware configuration.
Report prepared for: Siemens Drive Maintenance / Automation Engineer
Date: [Insert current date]
Firmware reference: SINAMICS parameter manual, List Manual (LH1)
In Siemens SINAMICS drives (like the G120 or S120), Fault F07902 indicates a Motor Stalled condition. This happens when the drive detects that the motor has stopped rotating for longer than the set delay time, even though the drive is trying to run it.
Here are three post options tailored for different audiences:
Option 1: Quick Troubleshooting (Best for LinkedIn/Professional Forums)
Headline: Dealing with Siemens Fault F07902? Here’s the fix. 🛠️
If your SINAMICS drive just threw a "Motor Stalled" error, don't panic. Here is a rapid-fire checklist to get back up and running:
Mechanical Check: Is the motor actually jammed? Check for obstructions or a locked brake.
Motor Data: Ensure your motor parameters (p304–p311) match the nameplate exactly.
Identification: Redo the motor data identification (p1900=2) and static optimization.
Flying Restart: If this happens during an OFF/ON cycle, try activating the "Flying Restart" function (p1200=1).
Thresholds: If the motor is fine but the load is heavy, you might need to increase the current setpoint (p1610) or the stall delay time (p2178).
For more detailed steps, check the Official Siemens Support Portal. #Automation #Siemens #SINAMICS #Maintenance #Engineering
Option 2: Technical/Deep Dive (Best for a Blog or internal wiki)
Title: Troubleshooting the SINAMICS F07902 "Motor Stalled" Fault
The F07902 fault occurs when the difference between the set speed and actual speed exceeds the tolerance for a specific time limit. Common Causes & Fixes:
G120XA solution to warning F7902 motor out of step - 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:
Troubleshooting Steps
When encountering fault code 7902, follow these steps to troubleshoot and potentially resolve the issue:
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?
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. siemens drive fault code 7902
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
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
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
In the context of Siemens SINAMICS drives (such as the G120 or S120), Fault Code F7902 signals that the motor has stalled
. This critical protection fault occurs when the drive detects that the difference between the set speed and actual speed has exceeded a defined tolerance for too long, often because the motor cannot generate enough torque to overcome the load. Siemens SiePortal 1. Primary Causes of F7902 Mechanical Overload:
The load on the motor is significantly higher than its rated capacity, preventing it from reaching the set speed. Incorrect Motor Data:
The drive lacks accurate motor nameplate parameters (e.g., rated power, current, or power factor), leading to inefficient torque calculation. Incomplete Commissioning: Skipping the Motor Data Identification
(Motor ID) or rotating measurement prevents the drive from modeling the motor’s electrical characteristics. Encoder/Wiring Issues:
Faulty speed feedback from an encoder or incorrectly connected motor cables (e.g., swapping U and W phases) can cause the drive to "think" the motor is stalling. Brake Malfunction:
If a mechanical brake does not release properly when the motor starts, the motor will stall against the brake. 2. Standard Troubleshooting Steps
To resolve F7902, users typically follow a structured diagnostic process: Validate Motor Parameters: Ensure parameters such as (rated voltage), (rated current), and (rated speed) exactly match the motor's physical nameplate. Perform Motor ID: Re-run the identification procedure using
(identification at standstill). This helps the drive calculate the correct control parameters. Check Mechanical Integrity: F07902: Motor overspeed The actual motor speed has
Decouple the motor from the load to see if the fault persists. If it runs fine while decoupled, the issue is likely the mechanical load or an unreleased brake. Enable Flying Restart:
If the fault occurs when trying to start a motor that is already spinning (coasting), enable the "Flying Restart" function ( Adjust Fault Limits:
If the stall is temporary and expected for the application, you can increase the (delay time) or the (fault tolerance) to prevent nuisance tripping. Siemens SiePortal 3. Comparison with Related Fault Codes Key Difference Motor Blocked
Detected at very low speeds/standstill when the speed controller is at its limit. Motor Overspeed
The motor is spinning faster than the allowed maximum limit. Motor Stalled
The motor is running but cannot match the speed setpoint due to load or tuning. For detailed technical guides, engineers often refer to the Siemens Industry Online Support (SIOS) for a particular drive model like the sinamics drive motor fault 7902 - SiePortal - Siemens
This report provides a comprehensive overview of the Siemens Fault Code 7902 (F07902), often occurring in SINAMICS G120XA, G120, and S120 drives. 1. What is Fault F07902?
Fault F07902 indicates that the drive believes the Motor has Stalled (Motor Locked/Blocked).
Definition: The drive has detected a speed or position discrepancy indicating the motor is not rotating as expected based on its current frequency, typically after motor identification or during operation.
Result: The drive stops operating (OFF2 or OFF3 depending on configuration) to protect the motor and mechanics. 2. Common Causes
Missing/Incorrect Motor Data: The drive was not properly tuned to the motor.
Lack of Optimization: No Motor Data Identification (Static or Rotating) was performed.
Excessive Load: The motor is struggling to turn the mechanical load.
Improper Flying Restart: Attempting to start a motor that is already spinning without the appropriate "flying restart" function active.
Incorrect Cabling/Phase: Motor cables (U, V, W) are connected improperly. Brake Issues: The mechanical brake is not releasing.
Weak Power Module: The power unit cannot supply the required startup current. 3. Troubleshooting & Solutions (Step-by-Step) Follow these steps to diagnose and clear the fault: Re-commission Motor Data (Crucial): Perform a factory reset of the converter. Set p0010 = 1 (Quick commissioning). Enter exact motor nameplate parameters: Rated voltage ( ), current ( ), power ( ), Power Factor ( ), and speed ( Set p3900 = 3 (Quick commissioning for motor parameters).
Perform Static Optimization: Set p1900 = 2 to enable motor data identification at standstill.
Switch to "Hand" mode and press start to complete the measurement. Verify Mechanical and Electrical Connections:
Check for mechanical obstructions (brake locked, jammed load). Check motor cable connectivity.
If using encoder feedback, verify the encoder signal is accurate. Adjust Control Parameters:
Increase current setpoint: Increase p1610 (static torque setpoint) if stalling happens at low speeds.
Increase tolerance: Increase fault tolerance p1745 or delay time p2178 to make the drive less sensitive to minor stalls.
Activate Flying Restart: Set p1200 = 1 if the motor is still turning when the start command is given. Hardware Inspection:
Verify the braking relay control voltage. If the brake doesn't receive voltage to release, the motor will stall. 4. Relevant Parameters p0346: Motor excitation time (increase if too low) p1745: Fault tolerance p2178: Motor blocked monitoring time p1610: Static torque setpoint p1200: Flying restart 5. Summary Table Suggested Action Fault at startup Perform static/rotating motor ID (p1900=2/3). Fault under load Increase p1610 (torque) or check mechanical load. Fault after power failure Enable flying restart (p1200=1). Motor brake locked Check brake relay and release voltage. To get a more specific solution, tell me:
Which specific drive model (e.g., G120X, S120) are you using?
Does the fault happen at startup, or while the machine is running? Is your motor using an encoder?
I can then provide the precise parameter steps for your scenario. 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 For PROFINET:
: 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
The Siemens drive fault code F7902 (or 7902) Motor Stalled (or "Motor out of step"). This fault occurs when the drive detects that the motor is not rotating despite a torque or current being applied, or it has lost synchronism with the drive's output frequency. Common Causes Mechanical Overload:
The load is too heavy for the motor to start or maintain rotation, causing it to stall. Incorrect Motor Data:
The drive's parameters do not match the actual motor (e.g., rated current, power factor, or resistance). Incomplete Identification:
A "Motor Data Identification" (MotID) or static optimization run was not completed correctly during commissioning. Ramp Settings: The acceleration ramp ( cap P 1120
) is too short, or the torque limits are set too low to overcome initial friction. Phase Failure:
A loose connection or broken cable between the drive and the motor. Troubleshooting & Solutions Check for Mechanical Obstructions:
Manually rotate the motor (if safe) to ensure the load isn't seized or jammed. Verify Parameter Settings:
Cross-check the motor nameplate against the drive parameters ( Perform Motor ID: Re-run the motor data identification (
or similar, depending on the model) to allow the drive to "learn" the motor's electrical characteristics. Increase Current/Torque Limits: Check if the stall detection limits ( cap P 2175 cap P 2177 ) are too sensitive for your specific application. Extend Ramp Times:
Increase the acceleration time to give the motor more time to reach speed without hitting the stall threshold. If you are using a SINAMICS G120XA
, this fault is frequently tied to asynchronous motors that haven't undergone proper static optimization. You can view the specific fault history and timestamps using the Siemens STARTER software TIA Portal specific parameter numbers for a particular Siemens drive series, like the
Subject: G120XA solution to warning F7902 motor out of step - Siemens
Siemens drive fault code 7902 is a protective response to either genuine motor overheating or a faulty temperature sensing circuit. By following a logical diagnostic path—checking actual motor temperature, inspecting wiring, verifying parameters, and analyzing historical data—most instances can be resolved in under 30 minutes.
Remember: Never ignore 7902. While sensor faults are easy fixes, ignoring genuine overtemperature will lead to premature motor insulation failure, costly rewinds, or even a stalled production line.
For persistent cases, Siemens technical support can analyze a drive trace (via Startdrive recording function) to pinpoint whether the fault is load-related or hardware-related. Keep your motor parameters accurate, your cooling vents clean, and your sensor wiring intact—and fault 7902 will become a rare visitor in your maintenance log.
This article is based on Siemens SINAMICS documentation and field experience. Always refer to the official List Manual for your exact drive series and firmware version before changing parameters.
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)
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
This is a diagnostic and troubleshooting report for Siemens Drive Fault Code 7902.