How to Troubleshoot ABB ACS550 Fault F0022 Supply Phase?

Getting the ABB ACS550 Fault F0022? This "Supply Phase" fault indicates high DC link ripple caused by a missing input phase or blown fuse. Learn how to diagnose your rectifier and power supply.

The ABB ACS550 drive is designed to rectify incoming AC power into a smooth, stable DC voltage. If your display shows Fault F0022 (Supply Phase), the drive has detected that the DC link voltage has become "unstable" or "rippled."

In plain English: The drive is missing one of its input phases (L1, L2, or L3). Because one phase is gone, the DC bus is no longer being charged steadily, causing a "ripple" effect that the drive identifies as a major power supply fault.

What Triggers Fault F0022?

• Missing Input Phase: A utility power issue, a loose terminal, or a tripped circuit breaker has cut off one of the three phases.
• Blown Fuse: A fuse upstream of the drive has blown, leaving the drive running on only two phases.
• Rectifier Failure: One of the internal diodes in the drive's rectifier bridge has failed, preventing it from converting one phase of AC power.
• Loose Terminals: A high-resistance connection at the input terminal block is causing an intermittent phase drop-out.

Step-by-Step Troubleshooting Guide

Safety Warning: The ACS550 contains high-voltage DC capacitors. Always wait at least 5 minutes after disconnecting power to allow for discharge. Always verify zero voltage with a multimeter before touching wiring.

1. Check Input Supply Voltage

Before assuming the drive is broken, verify the power coming into the building or the cabinet.

• Measure the voltage at the input terminals (L1, L2, and L3) while the drive is powered.
• Compare the readings: L1-L2, L2-L3, and L1-L3.
• If one phase is missing or shows a significantly lower voltage than the others, you have confirmed an upstream power issue (fuses, contactors, or utility supply).

2. Inspect Upstream Protection

• Check the fuses in the disconnect switch or the circuit breaker feeding the drive.
• If you find a blown fuse, do not just replace it. Investigate why it blew. A shorted rectifier in the drive is a common reason for a fuse to blow upon energization.

3. Testing the Drive Rectifier

If your input power is perfect, the failure might be inside the drive's rectifier bridge.

• Set your multimeter to "Diode Test" mode.
• Test the input diodes by measuring between each input terminal (L1, L2, L3) and the DC bus terminals (DC+ and DC-).
• You should see consistent diode voltage drops across all phases. If one phase shows "Open" or "Short" compared to the others, the internal rectifier bridge has failed.

4. Check Connections

Vibration can cause terminal screws to back out over time. Even if you have power, a loose connection creates heat and causes the drive to "see" a missing phase. Tighten all input terminal screws on the ACS550.

How to Reset the Fault

1. Identify and repair the missing phase (e.g., replace the fuse or tighten the loose wire).
2. Press the [Reset] button on the control panel.
3. If the fault triggers immediately upon power-up, stop. This strongly indicates a failed internal rectifier diode, and the drive unit will likely need to be replaced.