The controller shows E013 Undervoltage, and the generator breaker will not close.

Safety first: Keep the generator isolated from the load while troubleshooting undervoltage. Lock out the breaker to prevent accidental closure.

• Check no-load voltage: Start the generator with the breaker open. Measure the line-to-line voltage. If significantly below the rated value, suspect excitation issues.
• Inspect AVR and excitation circuit: Verify all connections to the AVR, including field leads to the rotor. Look for burnt or loose terminals.
• Test with reduced load: If voltage collapses only under load, gradually apply load while monitoring the voltage. A sudden drop may indicate a winding fault or an undersized load step.
• Controller settings: Confirm that the undervoltage threshold and delay are correctly set for your generator in the Atlas Copco controller.

If the alternator windings or rotor are suspected, further testing (insulation resistance, winding resistance) by a specialist is required.