Generator hot to touch

walkerlakeprinter

walkerlakeprinter

Senior Member
I'm guessing that a generator should not get so hot it is hot to the touch.
I ran my engine for several minutes and after I shut it down, the generator felt really hot to the touch. What might be going on? This generator worked fine 10 years ago before i dismantled the car. I changed nothing. I haven't checked the generator output yet. Just wondering where to start.
 
How much charge does the ammeter show ? Is it charging too much ?

Is the generator hot without the engine running ? I'm wondering if the cut-out is stuck and the generator is trying to motor.
 
Sounds like it's working too hard. Either the battery is low on charge or the 3rd brush is set for too high an amperage output. It also may be a bit of both. Make sure the commutator hasn't corroded and that the brushes are in good condition. Bearings might also be a bit of the cause if they are crusty or need lubrication. 10-years is a long time for an automotive accessory to set around. Also make sure all your terminal connections are clean and tight.
 
I agree with Patrick in post number 4 . I would tap on the cutout cover in an attempt to make the points in the cut out unstick . The ammeter should tell the story if the cutout is stuck . If the ammeter continues to show a discharge I would either disconnect the cut out or the battery . If left connected it will either kill the battery ior burn out the generator .
 
The ammeter doesn't show any major discharge unless I use the brakelights. I don't have the light switch attached to the steering column yet. Would that affect anything? I see no movement on the ammeter when the engine is running at all. The generator does not get hot when the engine is not running....but it sure took a long time to cool down.
 
When I disconnect the battery while the engine is running, the engine quits immediately. Is that an indication that the generator is not working at all? That plus no indication on the ammeter.
 
Yes, that would indicate that the generator isn't charging . The problem could be with the cut out . If the points in the cut out fail to close at the proper time the generator won't charge . Reproduction cutouts can be a problem .
 
If the cutout is faulty and the contacts not closed the generator can get up to well over 30 volts internally then will get very hot and finally burn out .Ground the output post to drive home if this happens on the road to prevent this .

John in no weather today Suffolk County England .
 
I think I need to re-polarize the generator. The instructions I find say to jumper between the two terminals on the cutout. Which two terminals? I only see the one with two wires attached. See photo.
 

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The other terminal is the one going to the generator output stud. Start the engine, then jump the 2 terminals together to see if you get output.


Disconnect the jumper before shutting down the engine.
 
I tried repolarizing with the engine running. I touched the jumper to the terminals for a second. Is a brief touch enough? One thread says just a nano-second, and another says just to remove the jump before shutting down the engine. Electrical questions make my head hurt.
 
One second or 5 seconds is fine with the engine off, but don't leave the jumper wire on with the engine off, or the generator will try to motor and will overheat.


With the engine running, the generator output will be fed through the cutout into the battery. Jumping the 2 cutout terminals with the engine running just confirms the power is getting through if the cutout contacts aren't making good contact to each other.
 
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