oL1 Overload (Motor) fault in delta drive

oL1 Overload (Motor) fault in delta drive troubleshooting

Description

oL1 is the "Electronic Thermal Relay" protection for the motor. The drive calculates the motor's heat accumulation based on the current output and time (I²t). If the motor runs above its rated current for a prolonged period, oL1 trips to save the motor insulation.

Causes

1. Heavy Load: The motor is undersized for the application, or the load has increased (worn bearings, dry gearbox).
2. Wrong Settings: The "Motor Rated Current" parameter (usually Pr.05-01) is set incorrectly (lower than the actual nameplate).
3. Low Speed Operation: Running a standard AC motor at low speeds (e.g., 10Hz) reduces its self-cooling fan efficiency, causing it to overheat even at rated amps. The drive calculates this derating.

Solution

Match the drive to the motor and load:
1. Verify Parameters: Check that the Motor Rated Current setting matches the motor nameplate exactly.
2. Load Check: Check current draw (Amps). If it exceeds the nameplate, reduce the mechanical load or gear down.
3. Cooling: If running at low speeds continuously, install a forced cooling fan on the motor or switch to an Inverter Duty motor.
4. Curve Adjustment: Ensure the Electronic Thermal Overload relay setting (Pr. 06-xx) is set to "Standard Motor" or "Inverter Motor" correctly depending on what you are using.