What can cause the ATV312 drive to trip on an OLF fault?

Issue:
ATV312 trips on an OLF fault

Product line:
Altivar 312

Environment:
All range All serial number

Cause:
The motor is pulling too much current?

Resolution:
Motor overload (OLF) is triggered by the motor pulling current above the Motor Thermal Current (ItH) that is programmed into the drive.  This motor protection is based on a time-inverse curve. The higher that the current is above the ItH setting, the less time it will take to trip on OLF.  Troubleshooting includes:

Check that the motor nameplate info is programmed correctly into the drC menu.
Check that the motor thermal current (ItH) is programmed at the motor FLA.
Check that the load is not too large for the motor.
Check that the current limitation (CL1) is not too low.  Typically set variable torque loads at 1.2 x Motor FLA and constant torque loads at 1.5 x FLA.
Verify that the motor current is balanced in all three legs and not exceeding the motor FLA.

The Motor thermal state (tHr) can be displayed in the Monitoring menu (SUP).  The drive will trip when tHr reaches 118%.  It will not allow a reset until tHr drops below 100%.

Released for:Schneider Electric New Zealand