Generator trips on E-13, load drops, controller indicates overvoltage

Safety: Overvoltage can damage connected equipment. Isolate the generator from the load immediately. Disable automatic start.

• Verify voltage: Use a true-RMS multimeter to confirm the actual line voltage at the generator terminals. Compare with controller readings.
• Inspect AVR wiring: With power off, check the AVR sensing and excitation wiring for loose or mis-landed connections. Correct any wiring errors per the CAT schematic.
• Neutral and ground: Ensure the generator neutral connection is secure and that grounding is per CAT installation instructions. A floating neutral can cause unstable voltage readings.
• Controller settings: Confirm that the controller is configured for the correct nominal voltage and sensing method (3-phase 3-wire/4-wire, etc.).
• Test under no load: After corrections, run the generator without load and monitor voltage stability.

If overvoltage persists, the AVR is likely defective and should be replaced with a CAT-approved unit by a qualified technician.