Hi all. So I recently woke up my Cadillac from a long winter of sitting. Started up and ran great, but I saw that once the generator started charging it was arching fairly heavily from inside near the brushes.. it was at night so much easier to notice. The car was charging fine and the generator currently in it has been in there about 2 1/2 seasons so the brushes should be seated just fine. I guess my question would be, is it anything to worry about considering it is charging ok? I just don't want the old girl to go up in flames on me. Thanks in advance for any input. Sent from my XT1650 using The H.A.M.B. mobile app
How is the brush wear? Springs still holding the brush tight? There will be some minor sparking or glowing, what ever you want to call it but nothing that should be alarming. Is the comm glazed? Try running a comm stone over it,
Normaly there is a dust band covering case were brushs can be seen,if thats missing or out of place a bit,you would see sparky looking. It's normal for them to do .
Is there not a cover that goes to cover the brushes? Most brushes spark a little, and at night they would look brighter. Can’t say if yours is excessive. Bones
Thanks for the input guys.. like I said it seems to be charging fine and there is definitely no dust cover to be seen. I'll check the old gen and see if there is a cover on that one and Rob that one if possible... Also re route my fuel line a bit for good measure!! [emoji18] Sent from my XT1650 using The H.A.M.B. mobile app
I'll definitely get in there and check those springs for good measure. At first glance everything looked clean but I did not think to check the spring tension.. thanks for your input. Sent from my XT1650 using The H.A.M.B. mobile app
Maybe you know all this already and don't need a lecture - but there's basically just one chance to seat brushes, before generator is put into service. A long strip of garnet sandpaper about as wide as the commutator is used, the brushes are made of carbon and very soft so it only takes a few seconds. The idea is that each brush presents the maximum possible surface area and conforms closely to the shape of the commutator. Otherwise they will arc and burn. They do spark some in normal operation, but if it's showering sparks like a bench grinder that might be what's going on.
The copper may have gotten a bit of corrosion on it over the winter that is causing less than perfect contact until it wears off too.
It's not too severe.. I think the fact that it was dark in my garage when I fired it up may have spooked me a little more than it normally would.. thanks for the info though.. good to know! Sent from my XT1650 using The H.A.M.B. mobile app
If you can feel the section between the commutator segments (the insulated bit, or the little stripes that are on the commutator), they should be a little bit lower than the copper on either side. If they are level with the copper, your commutator needs to be undercut. Sometimes the sparking you see is because the brushes are not 100% in contact with the copper (they are riding on the mica which is what the stripes are). You can do this yourself, but you have to pull the armature out. A hacksaw blade ground down to make a sharp "hook" can be used to scrape away a few thousands of an inch of the mica, then clean up the copper with some 1200 grit and blow out the dust.
With your mirror & flashlight, look for brush condition. New brushes are 1'' long from armature to the spring; check wear by the amount of brush showing outside brush holder. When you can't see carbon, it's brush time.
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