# Generator no power



## Tanner01 (Jul 22, 2016)

Hi everyone. I have a Briggs 7000 watt generator. I did a quick check for the avr by putting 12 volts to the brushes and getting 90 volts ac from the output. I was told as long as I had more than 50 volts ac then the avr must be shot. So thinking the avr was toast I put a new one on. Still with same problem of no power out the plugs (only about 1-2 volts ac). So I double checked with the brush test, still get 90 volts output. But I checked the volts dc coming out of the avr thinking there should be 12-24 volts out the avr to the brushes and it's only about 1-2 volts dc. Is there something I'm missing? Is 90 volts ac too high on a 12 dc charge to the brushes? Is there a way to check the new avr to see if the new avr is just bad? The unit doesn't even have an hour on it. Any input is greatly appreciated!


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## Osviur (Sep 7, 2015)

*Avr*

Hi Tanner01,

The AVR is fed by a portion of the stator's main windings. There are two wires comming from the stator to feed the AVR electronics and the field windings, two from the AVR to the rotating field and two from the main stator's output coils for sensing the output voltage.

When you feed the rotating field via the brushes, you are replacing the feed AVR's function, but not the regulation function, it is done comparing the main output voltage with a reference voltage generated inside the AVR, taken from the stator main output coils.

Check for incoming AC voltage from the stator to the AVR (engine on), in your picture, those that are near to the brush cables. If there is not voltage, check for continuity between the input wires ( engine off), they connect a derivation from the main coils, carrying part of the main output voltage.

I hope this note will help you.

Regards.


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## SolutionFUTA (Aug 27, 2020)

There is this primitive test that we do perform as a quick check for alternator assembly functionality, I hope you'll find it helpful.

If your rotor is the brush type, set your multimeter to check for resistance, place one probe of the meter on one of the rings and the other probe on the second ring. You should get around 90+ to 100+ ohms depending on the rotor size. Still on the rotor, place one probe on a ring and the other on any metallic part of the rotor. This time, you shouldn't get any reading on the meter otherwise, the rotor is bad.

For the stator, we have the main winding, excitation winding and a winding for voltage regulator signal and maybe other windings (not to reckon with yet). 
The signal winding and main winding are connected somehow, i.e. they are continuous. The exciter winding is not continuous with any. Use multimeter to check continuity of the main winding and the signal winding, check exciter winding continuity. Check if none of the winding is continuous with the status body.


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