Cause : Stall prevention (overcurrent) comes when the output current of the inverter increases, the stall prevention (overcurrent) function activates.

The following section explains about the stall prevention (overcurrent) function:

1. During acceleration: When the output current (output torque under Real sensorless vector control or vector control) of the inverter exceeds the stall prevention level (Pr.22 Stall prevention operation level, etc.), this function stops the increase in frequency until the overload current decreases to prevent the inverter from resulting in overcurrent trip. When the overload current has reduced below stall prevention operation level, this function increases the frequency again.
2. During constant-speed operation: When the output current (output torque under Real sensorless vector control or vector control) of the inverter exceeds the stall prevention level (Pr.22 Stall prevention operation level, etc.), this function reduces frequency until the overload current decreases to prevent the inverter from resulting in overcurrent trip. When the overload current has reduced below stall prevention operation level, this function increases the frequency up to the set value.
3. During deceleration: When the output current (output torque under Real sensorless vector control or vector control) of the inverter exceeds the stall prevention level (Pr.22 Stall prevention operation level, etc.), this function stops the decrease in frequency until the overload current decreases to prevent the inverter from resulting in overcurrent trip. When the overload current has decreased below stall prevention operation level, this function decreases the frequency again.

Check point

1. Check that the Pr.0 Torque boost setting is not too large. 
2. The Pr.7 Acceleration time and Pr.8 Deceleration time settings may be too short.
3. Check that the load is not too heavy. 
4. Check for any failures in peripheral devices.

Solutions

1. Gradually increase or decrease the Pr.0 setting by 1% at a time and check the motor status.
2. Set a larger value in Pr.7 Acceleration time and Pr.8 Deceleration time.
3. Reduce the load.
4. Try Advanced magnetic flux vector control, Real sensorless vector control, or vector control.
5. Change the Pr.14 Load pattern selection setting.
6. The stall prevention operation current can be set in Pr.22 Stall prevention operation level. (Initial value is 150%.) The acceleration/deceleration time may change. Increase the stall prevention operation level with Pr.22 Stall prevention operation level, or disable stall prevention with Pr.156 Stall prevention operation selection. (Use Pr.156 to set either operation continued or not at OL operation.)