Alarm A07991 is triggered when the VFD's internal firmware expects a motor data identification (Motor ID / Auto-tune) routine to run. This standard automated procedure calculates internal variables like stator resistance, leakage inductance, and magnetic saturation to optimize motor control and efficiency.
The Siemens fault code (often searched as 0a7991 ) specifically indicates that Motor Data Identification is activated . This is not a critical equipment failure but rather a status alarm triggered during the commissioning or configuration phase of Siemens SINAMICS drives , such as the G120, G120C, and G150 series. Understanding Alarm A07991
If you are working with Siemens SINAMICS drives—particularly the —you might encounter the alarm code A07991 , often displayed as "A07991 (N) Drive: Motor data identification activated". While classified as an alarm (indicated by the 'A'), it directly inhibits normal drive operation, preventing the motor from running until the identification process is completed or bypassed. siemens fault 0a7991
Are you seeing this on a or did it appear suddenly on a running machine ? Fault A07991 cannot be cleared on SINAMICS G120C drive
Modifying parameters only updates temporary drive memory. You must save it permanently to prevent the alarm from returning during the next facility power outage. Alarm A07991 is triggered when the VFD's internal
If your machine setup cannot tolerate diagnostic movements or a prolonged standstill test, you can turn off the routine inside the Siemens SiePortal parameter settings.
The most common solution is allowing the drive to do its job. This is not a critical equipment failure but
When both occur simultaneously:
The most effective way to clear the code is to allow the drive to perform its automated diagnostic routine.