Generator troubleshooting

[aarolar]

So I bought a nearly new looking troybuilt genset this weekend for 20 bucks. It cranks and runs on one pull but has a gremelin in the power output.

I found a video on testing the regulator that required hooking a 12 volt battery to the brushes and looking for 60 volts at the output and at first I didn't get anything so I pulled the stator and rotor off and investigated everything looking for damage in the windings. Didnt find anything that stood out so I reassembled everything and just for slaps check it one more time and had 115 flash on the meter breifly, couldn't get it to repeat but the I pulled the battery out and attempted the test once more and this time I got two things. One was a small spark when I touched the ground to the battery and two was I had 80 volts at the plugs.

So I once again reassembled everything and it ran and put out power fine, I plugged in my air compressor to load it up and it ran great then I pulled it around the yard to jostle it some and tried it once more and still had good power so I considered it fixed.

Now fast foward to the next day I tried it again and now power again, it had never moved from where I left it. I pulled it apart again and noticed this time when I attempted to use a battery to energize the field I got no spark or voltage. From this I conclude there is something wrong with the brushes or rotor windings but Im no master generator mechanic can anyone else shed some more light on this situation?

This is the video I watched and the same generator I have.
<iframe width="560" height="315" src="https://www.youtube.com/embed/vN_2mb-dYGo" frameborder="0" allowfullscreen></iframe>

 

[Sagetown]

Could be the gen has rusted, and won't turn over, or worse.
I hadn't used mine in years , and it would squal and stop the engine from running. Finally, it did run, and I put it under a load for quite sometime. It has ran good ever since.

 

[matt167]

if it just does not output, take a corded drill, plug it in and turn the chuck a little to excite the circuit. It might just work

 

[aarolar]

I can get the rotor for around 250$ new brushes are pocket change as is a new regulator which I havent ruled out as the culprit yet. I only have 20 bucks in this deal so im not past buying a new generator head or even a used one if I can found it. I also am not sure what the possibility of having it rewound it yet.

 

[aarolar]

The drill trick did nothing tried that this morning real quick.

 

[Sagetown]

I can get the rotor for around 250$ new brushes are pocket change as is a new regulator which I havent ruled out as the culprit yet. I only have 20 bucks in this deal so im not past buying a new generator head or even a used one if I can found it. I also am not sure what the possibility of having it rewound it yet.

Rewinding shops vary in service costs. Shop around.

 

[aarolar]

Rewinding shops vary in service costs. Shop around.

I need to determine thats the problem first even then they may not touch it for less than a new one.

 

[aarolar]

It is consistently making 2.5 volts

 

[anlrolfe]

Remove the brush assembly and see if the slip rings have a dark glaze. This can stop or reduce excitation current through the revolving field. Rough them up with some super file emery cloth. Make sure that the brushes fully extend and contact the slip rings. If you flash the brushes with 9v battery you can get nearly full output voltage. If you see something(voltage) doing this then your problem is typically rectifier/regulator assembly probably less that $50

 

[aarolar]

Remove the brush assembly and see if the slip rings have a dark glaze. This can stop or reduce excitation current through the revolving field. Rough them up with some super file emery cloth. Make sure that the brushes fully extend and contact the slip rings. If you flash the brushes with 9v battery you can get nearly full output voltage. If you see something(voltage) doing this then your problem is typically rectifier/regulator assembly probably less that $50

Thank and I have done all that im not getting anything exciting the field with a 12 volt battery. I think I've pretty decided to just replace the generator head, northern tool has a 4000 watt brushless one for 299 and I found a coupon for 50$ off so in the end I'll still only be in it for 270$ but brushless with cleaner power.

 

[anlrolfe]

Its probably toast if you can't excite it right at the brushes and get output.
One last thing worth checking. See if there is a fusible link or overload device(breaker) is series with the output that could be open blocking output. Some of these have push button thermal overloads that are one hair above pure junk, flakey at best especially when they get water inside.
Direct swap to a brushless generator is quick and easy solution when you've got a good motor.

 

[aarolar]

I got it working just never took the time to respond ended up being a bad crimp at the connection between the field windings and slip ring I went ahead and soldered both up instead of the crimp connection.

Broken crimp

Repair job.

 

[anlrolfe]

Excellent!
Glad to hear that it was a cheap fit.
As Dad would have said "We're gonna take it apart and try to fix it. What's the worse we can do? It's already broken."