Causes of a OL1 fault on ATV21 or ATV212 drives.
Altivar ATV212, ATV21
All models, all serial numbers
OL1 is a drive overload fault. The motor is pulling to many amps and the internal overload is tripping.
OL1 is an overload fault.
ITH parameter under main menu AUF is what determines the overload settings for a motor. It is normally programmed to match motor FLA.
Confirm that the motor settings including uL, F415 and F417 match your motor name plate.
Check ACC time and make sure it is not too short a ramp up time.
Set AU1 to 0.
Measure current draw by motor if possible at the output to the motor. If the current draw surpasses ITH value then it will eventually fault out on OL1 given enough time has passed.
Check for power drop in the line side of the drive.
Set PT to 0.