Cause : Stall prevention stop comes when the output frequency has fallen to 0.5 Hz by stall prevention operation and remains for 3 s, a fault (E.OLT) appears and the inverter trips. OL appears while stall prevention is being activated.

1. When speed control is performed, a fault (E.OLT) appears and the inverter trips if frequency drops to the Pr.865 Low speed detection (initial value is 1.5 Hz) setting by torque limit operation and the output torque exceeds the Pr.874 OLT level setting (initial value is 150%) setting and remains 3 s.
2. Check the motor for the use under overload.
3. Check that the Pr.865 and Pr.874 values are correct.
4. Check if a motor is connected under PM sensorless vector control.
5. Reduce the load.'Change the Pr.22, Pr.865, and Pr.874 values. (Check the Pr.22 setting under V/F control and Advanced magnetic flux vector control.)