: Ensure all hardware and motor parameters are correctly entered in the configuration. Run Motor Identification : Navigate to the commissioning folder.
Following a power cycle (24V or 400V) if the motor data identification (p1900) was set to be performed at the next power-on. Causes of Alarm A07991
When a Variable Frequency Drive (VFD) is paired with an electric motor, it must build a highly accurate mathematical profile of the motor’s internal electrical characteristics (such as stator resistance, leakage inductance, and magnetizing current). This process is known as .
: Set this to "Inhibited" to disable the motor data identification and rotation test. siemens fault 0a7991
The code (often logged as 0A7991 or alarm A7991 ) on Siemens SINAMICS variable frequency drives (VFDs) indicates that the Motor Data Identification routine is activated . It frequently appears during the initial setup or commissioning of drives like the Siemens SINAMICS G120C , G130, G120, and S120 series.
Prepare:
Ensure the motor is at a standstill and the configuration is complete. : Ensure all hardware and motor parameters are
: If the fault persists, some users recommend setting the control mode to "V/f standard".
For experienced technicians, resolving this is straightforward by either completing the identification run or disabling the parameter. For beginners, it can be confusing because the drive will not run normally until this "active" state is cleared.
: The most common cause is a new setup where the user has selected a motor ID run (e.g., through parameter Parameter Changes Causes of Alarm A07991 When a Variable Frequency
Users often see together with A8526 ("Drive: PLC signal not valid"). This typically means the PROFIdrive telegram from the PLC is not sending the correct status word, or the motor ID run failed, causing the PLC to stop sending commands. Solution for A8526/A07991 Combo: Address A07991 by performing the ID run.
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If you are staging components inside a panel shop or lab environment without a physical motor load connected to the power modules, the drive will lock up or fault out if it tries to pass a diagnostic current.
Navigate directly to the drive parameters using your control panel or TIA Portal.