Output phase loss is one of the common malfunctions in frequency converter operation. For Oulu frequency converters, output phase loss is displayed as ERR/FU13 on the operation panel. The causes and troubleshooting methods for output phase loss are as follows:

1. Motor failure: Check for open circuits in the motor.

2. Abnormal wiring between the inverter and motor: Troubleshoot peripheral connection issues.

3. Unbalanced three-phase output from the inverter during motor operation: Inspect the motor's three-phase windings and resolve any irregularities.

4. Abnormal drive board or IGBT module: Seek technical support for further diagnosis and repair.