Generator runs but produces no AC voltage at terminals
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Open the generator output breaker and ensure no backfeed from the ATS or mains. Turn controller to OFF before opening the alternator terminal box.
- Measure terminal voltage: With the generator running and breaker open, measure line voltage. If zero or very low, suspect excitation issues.
- Check AVR supply: Verify that the AVR is receiving its supply and sensing voltages. Inspect and tighten all connections.
- Field circuit: If accessible, measure resistance of the rotor field winding. An open circuit indicates rotor failure.
- Field breaker: Some sets have a small breaker feeding the AVR/field. Reset if tripped and investigate cause.
- AVR replacement: If wiring and field are sound, replace the AVR with the correct Kohler-SDMO specified unit.
Loss of excitation diagnosis often requires a generator specialist with appropriate test equipment.
Repair Difficulty
Required Part
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