6 volt Generator brushes squeal like a pig!

gingerkid

gingerkid

Junior Member
My early 6 volt generator squeals like a damn pig! still works its not the bushing or bearing its the brushes i've replaced them cleaned the armature sanded the armature and brushes done everything i can think of, i put dielectric grease on it stopped but quit charging any tricks?
thanks for the info!
 
Brushes can make some noise until they take a set to the commutator. It's possible what you are hearing is the commutator segments rotating across the brushes. Once the face of the brushes conform to the commutator they should quit down. Don't put any type of grease on them.
 
gingerkid said:
My early 6 volt generator squeals like a damn pig! still works its not the bushing or bearing its the brushes i've replaced them cleaned the armature sanded the armature and brushes done everything i can think of, i put dielectric grease on it stopped but quit charging any tricks?
thanks for the info!
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curious as to why the brushes have been targeted as the source of the noise, as they've been replaced and the armature cleaned, etc. AFAIK, they may cause some noise, but rarely squealing.

IME, it's always been the generator's bearings or bushings that squeal (the generator may have a couple of oiling ports, BTW), or perhaps the belt or any other device connected to it. good luck!
 
hueyhoolihan said:
curious as to why the brushes have been targeted as the source of the noise, as they've been replaced and the armature cleaned, etc. AFAIK, they may cause some noise, but rarely squealing.

IME, it's always been the generator's bearings or bushings that squeal (the generator may have a couple of oiling ports, BTW), or perhaps the belt or any other device connected to it. good luck!
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hueyhoolihan in trying to find the squeal while it was running i touched each brush pulled them off the commutator it immediately stops squealing i had originally thought it was bearings and bushings it obviously wasn't.
 
gingerkid said:
hueyhoolihan in trying to find the squeal while it was running i touched each brush pulled them off the commutator it immediately stops squealing i had originally thought it was bearings and bushings it obviously wasn't.
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understood...

i might suspect that a brush spring or two was too tight or too loose. IIRC, forces generated on the brushes of a generator can be easily adjusted to exert whatever force is necessary. might try adjusting a spring or two. and if that fails i might remove each brush, in turn, to isolate which brush or brushes are making the noise. and if THAT fails i might think about finding another source for some brushes.

after all...with the quality of aftermarket parts these days being what they are....
 
and another thought...

if ALL the brushes were removed and only then was the squeal eliminated, it might indicate that a bearing or more likely a bushing was worn to the point where any slight asymmetry in brush force could push the armature out of its correct rotational axis and bear in such a way on a bearing or bushing to create a squeal.

granted, a little far-fetched, but at this point the cause will probably be an unlikely one, in that the obvious sources of the noise have been eliminated. i suggest this only because we're approaching a bit of the Sherlockian adage here: "When you have eliminated the impossible, whatever remains, however improbable, must be the truth.". --Sir Conan Doyle from "The Sign of the Four"--
 
hueyhoolihan, so very true on all counts, i spun it on the bench when i messed with the brushes and yes i do believe one or two were a little tight.
 
An intermittent loud squeal can be caused by a dry bushing. The longer it goes dry, the more permanent the squeal. A temporary fix is a couple of drops of oil in the bushing oil cup, the permanent fix being to replace the bushing itself.
 
Are the brushes from Ford? The carbon composition varies from Mfg. Ford brushes P/N 40-10047 have numbers indented into the carbon. If you inspect an original kit of three replacement Ford brushes, two of the brushes should have the same number and the third a different number. The single number is softer carbon and was made for the adjustable brush. The brush holders may be too wide allowing the carbon brush to move. The carbon brush should only move straight in or out smoothly.
 
To compliment Terry's post, here is a set of original Ford brushes. Note that there is a chamfer at the end of the brush that attaches it to the holder. That chamfered edge should face into the corner of the brush holder to orient the commutator end of the brush properly. Some aftermarket brushes don't have the chamfer resulting in the brushes being installed backwards.

As I mentioed in my video, sanding in the brushes to match the commutator surface is very important to gain full contact. Commutator diameters vary a lot after 90+ years, so this is an important step for proper operation.
Steve
 

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ndnchf said:
To compliment Terry's post, here is a set of original Ford brushes. Note that there is a chamfer at the end of the brush that attaches it to the holder. That chamfered edge should face into the corner of the brush holder to orient the commutator end of the brush properly. Some aftermarket brushes don't have the chamfer resulting in the brushes being installed backwards.

As I mentioed in my video, sanding in the brushes to match the commutator surface is very important to gain full contact. Commutator diameters vary a lot after 90+ years, so this is an important step for proper operation.
Steve
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Also on a generator commutator the mica insulation between the copper segments must be undercut below the surface level of the copper. The reason being that the mica is harder than the carbon brush material and does not wear down which causes the brush to make a bad contact with the copper segment. You can undercut by hand using a ground hacksaw blade or a special machine with a small rotary cutting blade. Starter motor comms dont require undercutting because the brushes are hard enough to wear down the mica between the copper segments. Regards, Kevin.
 
i guess what i was suggesting is this:

that the brass bushing (and/or possibly the bearing at the front too) at the rear of the generator may be worn to the point where the commutator's axle is being centered in the bushing not by the busing itself, as it's too worn to perform that task, but instead, is being centered, albeit poorly, by the three brushes and their springs. this would go a long way to explain why manipulation of the brushes while bench testing influences the squealing.

i would suggest the purchase of a generator bearing/bushing rebuild kit, maybe something like this: https://www.ebay.com/itm/297414491875
it may well be all that's necessary to fix your problem.

i don't know for certain, but it wouldn't surprise me if the rear plate on the generator could be removed, as it is necessary to replace the bushing, i think, while the generator remains in place. but the front bearing, if it's determined that it too needs replacing, may be a different story, IDK. ...could take less than ten minutes...but we all know how THAT goes, eh? :)
 
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Thank you for all the info, i believe i am going to ship it off and have it reconditioned that guarantees all is in good working order. i've been known to play wreck it ralph! lol i had it apart a couple times lost screws, found the screws 2 days later, lost a spring, swore alot drew blood... came back the next day and put it all back together now the squeal comes and goes at random.
 
One of my old manuals had photos of the technician cutting and installing aluminum oxide abrasive paper, abrasive out, on the commutator with thin cellophane tape to hold the paper on. The brushes are installed and then the commutator is turned by hand to seat the brushes to the proper radius. Rebuilders may have had a rotating fixture to do this but I've not seen one. Most are self seating and seat during power generation with no issues.

If that doesn't work, either the commutator could use a turn in a lathe or the current brushes may not be a good material for the job. Checking squareness of the brush holder to the commutator may be difficult but a good visual inspection could reveal if there is a bent holder or something of that nature.
 
It just so happens that I was sanding in model A generator brushes this morning using a KR Wilson brush sander. It makes the job quick and easy. Itook a few photos.
 

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