E011
Atlas Copco Incorrect Phase Rotation / Phase Sequence Fault

The controller shows E011 Phase Sequence Error when attempting to transfer load.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Incorrect generator output wiring, Reversed phases at ATS, Faulty phase sequence sensing module, Loose connections on voltage sensing leads

How to Fix / Troubleshooting

Safety first: This is a live AC power issue. Only qualified personnel should work inside the generator terminal box or ATS. Isolate all power sources before opening covers.

  • Verify phase rotation: Use a phase rotation meter on the generator output terminals (L1, L2, L3) and compare it with the mains supply rotation at the ATS. Both should match (e.g., ABC).
  • Inspect wiring: Check that the generator output cables are connected to the correct terminals in the ATS and main breaker as per the Atlas Copco wiring diagram.
  • Check sensing leads: The controller uses voltage sensing leads to detect the phase sequence. Ensure these small control wires are correctly connected and tight.
  • Correct phase order: If the rotation is reversed, swap any two phases at the generator output or ATS (with power isolated) and re-test.

After correcting the wiring, clear the E011 alarm and perform a test transfer under supervision.

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Repair Difficulty

Hard 4/5

Required Part

Phase Sequence Sensing Module
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