Cause : Rescue Operation Power Supply Deterioration Error comes when the DC bus voltage dropped below S4-12 * (S4-13 - 10%), or 100 ms after triggering Rescue Operation, the DC bus voltage did not reach S4-12 * S4-13 before the motor started.

1. Check the DC bus voltage setting for Rescue Operation (S4-12).
2. Lower the speed reference set for Rescue Operation (S4-15).
3. Check the backup power supply. It may need to be replaced with another UPS if it has become worn and can no longer provide enough power.