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

1. Check the motor for use under overload.
2. 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 setting and remains 3 s.
3. Check the motor for the use under overload.