F10
MTU Onsite Energy
Generator Output Overvoltage
Controller displays F10 – Generator overvoltage alarm/shutdown
Advertisements
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.
Advertisements
Possible Causes
AVR (Automatic Voltage Regulator) failure, Incorrect AVR sensing wiring, Loose or broken voltage sensing leads, Incorrect voltage setpoint
How to Fix / Troubleshooting
Safety first: Open the generator breaker and isolate the generator from the load before troubleshooting. High voltage is lethal.
- Verify actual voltage: Measure line-to-line and line-to-neutral voltages at the generator terminals with a true RMS meter. Confirm that the overvoltage is real and not a sensor error.
- Inspect sensing leads: Locate the AVR in the generator terminal box. Check the voltage sensing wires from the stator to the AVR for tight connections and correct phasing per the MTU wiring diagram.
- Check AVR settings: Verify that the voltage adjustment potentiometer or digital setting on the AVR is set to the correct nominal voltage (e.g., 400/480 V). Adjust carefully if needed.
- Test AVR: If voltage remains unstable or high despite correct wiring and settings, the AVR may be defective. Replace it with the MTU-specified AVR model.
- Inspect excitation circuit: Check the exciter stator and rotor connections for shorts or grounds that could affect regulation.
- Test under load: After repairs, clear the F10 alarm and test the generator under load while monitoring voltage stability.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Automatic Voltage Regulator (AVR)
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements