Kirby G4 Armature

[repairman]

I have a Kirby G4 where the brushes are slightly arcing and I wanted to know if I need a new armature because there is a ring worn into the commutator. If I run my finger across, I don’t feel a groove or cut and it’s all a smooth surface. So is the armature toast, or do I need to get new carbon brushes and seat them with a stone? If you look in the 3rd picture, you can get a better visual of the ring.

 

[lesinutah]

Hey

Notice where the wear is on commuter. It's where carbon brushes hit it. It looks good to me.
Les

 

[tolivac]

Looiks pretty normal.

 

[repairman]

I am aware of where the brushes hit the commutator. I just want to know if the small line in the middle of the middle mark is a sign of death as seen in the third picture.

 

[broomvac]

Looks great to me—and yes, I see the ring you speak of. If that were my vacuum, I would not be concerned. In fact, it looks cleaner than a number of (also good) armatures I have come across.

But, just to play the devil’s advocate, let’s say the armature is actually damaged. What’s the worst that could happen? One day it would just quit working and at that point you would have to get a new armature anyways. Using it until it fails shouldn’t cause any collateral damage. You would simply get a few more miles out of the original armature.

Nevertheless, I don’t think you will ever see that armature fail and you will able to save yourself some cash by not getting a new one.

 

[dysonman1]

The armature looks fine. Try to avoid prolonged use on HI speed (hose use), and you'll be fine.

 

[panasonicvac]

They look fine. One thing that you could do if you want to, there's some motor armature cleaning stones that you can do if you want the armature to look nice but I can't promise that the black rings would go away completely.

 

[madman]

Maybe just wipe the commutator the whole way 'round with a little alcohol - just to make sure it's not oily. Otherwise... looks great to me.

 

[huskyvacs]

The ring you describe is actually just the copper being stained from years of carbon buildup, that is normal. There will be more wear in the middle because that is where the brushes are pressed against the armature at their strongest. Both the armature and brushes still look new, like its been barely broken in.

Some arcing is normal, it's where it becomes a huge arc that envelops the motor and starts melting wires that can be an issue.

This is what would be an example of a bad arcing and a bad armature, where it is actually chasing the armature all the way around and is throwing sparks out of the fan housing:



Your armature can use a little bit of polishing up if you want, I followed this video:

 

[texaskirbyguy]

Some very fine sandpaper (like 800 or higher) can clean it up but as it is, it looks fine. If very little arcing, I would not even worry about it. Even after the brushes wear a visible groove into the commutator, it can still be used. Those bars are pretty thick. That one you show still has lots of life in it.

 

[bikerray]

If it's just some sparking along the edge of the brush that's normal. If the discoloration bothers you then clean it up with a seating stone. Just be careful using the stone, you want to clean it up not grind it down to nothing.

 

[anthony]

i cant believe what i am reading

DO NOT GO ANYWHERE NEAR A COMMUTATOR WITH SANDPAPER or anything else abrasive

 

[madman]

To each their own, I suppose.

I think sometimes people hear 'sand paper' and immediately think it's 80 grit. 800 grit, on the other hand, is more like emery cloth. It's leaving 'sanding' territory and heading into 'polishing.' Often if I say to someone to use sandpaper to clean electrical contacts they'll try to educate me about how bad that is, and that I should use a contact burnishing tool instead... which is literally just a fancy strip of 1000 grit sandpaper. It's all a matter of semantics, I suppose.

Anyhow, me personally, I wouldn't use sand paper unless the commutator was really bad. For a little freshening up, a ScotchBrite pad will do just fine. And yeah, it's technically abrasive too. If you wanted it really abnormally perfect, I suppose you could sand with increasingly higher grits until you hit 3000, but I believe it's wholly unnecessary.

 

[vaclab]

Very Fine Sandpaper And/Or Polishing Stone

are what I've been using for years to clean/polish my commutators. Cleans the carbon build up off and trues up the surface so that the carbon brushes spark less and make a better contact which gives a higher rotational speed.

Anthony, I don't understand your comment at all.

Want proof? Check out my latest Kirby G3 reassembly video around the 15 minute mark to witness commutator polishing. Listen to the motor speed rise and the wind down smooth out.