ABB · ACS850 Standard Program Firmware
This fault occurs when the drive, designed for a three-phase AC supply, detects a loss in one of its input phases. MotiFlex e100 uses dedicated hardware, while e180 monitors DC bus ripple. Operating with missing phases can lead to motor damage, uneven torque, or drive instability.
Click steps to track your progress.
1. Measure the voltage across all three incoming phases (L1-L2, L2-L3, L3-L1) at the drive's input terminals using a multimeter.
2. Inspect and test all fuses or circuit breakers in the main supply circuit for continuity or trip status.
3. Verify all power wiring connections at the drive's L1, L2, L3 input terminals and upstream contactors for tightness (torque specification: X Nm).
4. Monitor the DC bus voltage (e.g., using parameter P1-11) for excessive ripple or drop-out indicative of a missing phase.
5. Check for proper functioning of any upstream contactors by verifying coil voltage and contact continuity.