Controller displays “Overvoltage” and shuts down the generator; measured output voltage is significantly above nominal (e.g., >260 V on 240 V system).

Safety first: Turn generator OFF, open the generator output breaker, and isolate from the transfer switch. High voltage can damage connected loads—do not run the unit until corrected.

Steps:

• Visual inspection: Open the control/alternator compartment and inspect the AVR module and wiring harness for burnt components, discoloration, or loose connectors.
• Check sensing leads: Verify that the voltage sensing wires from the alternator stator to the AVR and controller are firmly connected and not pinched or broken.
• Controller settings: Using the Eaton controller menu, confirm that the system voltage and phase configuration match the actual installation (e.g., 120/240 V single-phase). Incorrect settings can cause misregulation.
• Test with meter: With a qualified person and loads disconnected, briefly run the generator and measure line-to-line and line-to-neutral voltages. If they remain high and unstable, shut down immediately.
• Replace AVR: If wiring and settings are correct, the AVR is the most common failure point. Replace with the exact Eaton-specified AVR for your model and retest.