Cause : Speed deviation excess detection comes when the inverter trips if the motor speed is increased or decreased under the influence of the load etc. during vector control with Pr.285 Speed deviation excess detection frequency set and cannot be controlled in accordance with the speed command value.

1. While deceleration stop is attempted, if the motor is accelerated against the stop command accidentally by the incorrect setting of the number of encoder pulses, etc., the deceleration check function (Pr.690) is activated to stop the inverter output.
2. Check that the values of Pr.285 and Pr.853 Speed deviation time are correct.
3. Check for sudden load change.
4. Check that the number of encoder pulses does not differ from the actual number of Pr.369 Number of encoder pulses.
5. Set Pr.285 and Pr.853 correctly.