Cause : n-act jump comes when the permissible change value of the speed encoder signal (P215) has been exceeded.

Additionally for synchronous motors (P095=12): The motor rotates with more than 2% of the rated speed at the time of inverter release. The inverter status "Ready for operation" is not exited.

1. Check the tachometer cables for interruptions.
2. Check the earthing of the tachometer shield.