How To Identify and Repair a Faulty Electric Generator

Electric generators have countless applications for both home and business use. They can provide a valuable backup source of electricity when primary sources fail, power mobile working units and may even be used recreationally on camping trips by providing a mobile source of power for lights, heating, and cooking. Unfortunately, many generators develop faults over time through improper use and cease to provide any useful output. If your generator has recently stopped outputting power, the following guide may help you to diagnose and repair the fault.

Beginning the diagnostics The most common fault with electrical generators lies with the automatic voltage regulator, or AVR. So here is what you should test for first. You will need:

  • An external battery (to supply a voltage directly to your generator's brushes)
  • A portable load bank (to display the generator's output and simulate a load)
  • A replacement AVR

Step 1: Disconnect the AVR

Your generator's AVR is likely to have become faulty as a result of being overloaded, and, as a result, will fail to provide the correct voltage to your motor. Disconnect the AVR to isolate this as the potential source of the fault.

Step 2: Connect your battery directly to the motor brushes

The AVR typically sends 24 volts to your generator's brushes. As a test, begin by applying 12 volts - half the AVR output - directly to your brushes from an external battery source. The load bank should show an output of approximately 50 volts coming from your receptacles. If this proves to be accurate, then it is highly likely that the fault lies with the AVR.

Step 3: Replace the AVR

Generator parts can be readily sourced from any local retailer, so call ahead with the make and model of your generator and check that they have parts in stock, or can at least order parts in. Simply request a new AVR for your model of generator and switch out the parts. If you have any doubts about this process, it may be worthwhile to photograph the original part while it is still connected as a reference for your later repair. Connect the new AVR as before, and your generator should now begin producing power.

No luck?

If your diagnostics show that the fault lies elsewhere than the AVR, it may indicate a more serious problem with the motor itself and a potentially more costly repair. In this instance, it is worthwhile to consult with a local repair shop who specializes in electric motor repairs for more direct advice and assistance. Good luck!