Stop produceing power after only 20 of running

Hi and wleome to FixYa, I am Kelly.

Pull off the small cover on the OUTSIDE of the end bell that covers the bearing and the brushes. Using a meter on resistance scale of R X 100 or R x 1000 probe the brushes and see if you read any resistance You should see a reading of much less than 1000 ohms that would be the rotor winding resistance. If you do not have resistance then remove the brushes and check the condition and LENGHT of the brushes. The brushes should be no less than 3/8" long. If you can get your test leads into the brush holes probe the slip rings and read the rotor resistance. You must read resistance under 500 Ohms. No resistance or can not reach the slip rings remove the end bell and test rotor resistance again but probing the 2 slip rings.

Most of the time the brushes wear out or break off when a generator just suddenly stops working.

Reinstall the end bell and read for a DC voltage reading of 3 - 9 volts across the brushes after you know the brushes are in good working order. No voltage then the AVR has failed. If you have voltage then the final tests would be continuity checks of the diode and capacitor in the end bell and finally the stator windings. The dilde will ony read resistance in ONE direction. It should NOT read open or shorted in both directions. The capacitor check use R x 10,000 and probe the capacitor terminals. Reverse the leads and probe it again. You should see a brief jump in resistance and the meter will drift to infinity EACH time you reverse the leads.

If you want parts information I need the model number off of the unit data plate to get that information for you.

Thanks for choosing FixYa,
Kelly