HI everyone I hope you are well,
I have a electric wheelchair motor 4 brushes that I removed the brushes from.
I have some theory questions and practical advice needed. It s my first time. I made sure to mark which sens goes the brush back in.

THEORY
First I guess It would be good for me to have an understanding of how the electricity runs from the motor brass brush hole to the brush.
1 I see there are 90 degree flapped 2 ears on each side of the brass part of the brush. Is this where the electric contact happens only?

2 Since there are 2 ears on each brush, is it that one ear is positive and the other is negative? If so, how can the electricity find its way since the hole brush holder is made of brass or metal so that is like a built in shortcircuit . Maybe it does not work that way and it is just electricity being sent in short intervals travelling by either or both brass ears .

3 Also is the dark part of the brush(chalk like material) electrified? because I see a copper wire from the brass part to the dark chalk part.
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PRACTICE.
I have been advise not to use sandpaper to remove the dark stuff in the inside of the brush hole to prevent some grinding material to go into the motor so I feel it is a wise advise to use stainless steal round brush to try to remove the black stuff kind of sticked on the side of one of the brush hole brass.

It seems that Deoxit is the product to use but I have a question : I see D5Hosa Caig Deoxit Contact Cleaner 5% Spray 5 Oz
wich is only 5 pourcent and a 100pourcent product called Labs D100L-16BX DeoxIT® D-Series D100L Mini-Brush Applicator

For now my need is only to clean the brush part. But in futur I might have to open the motor and clean the armature. I would prefer buying one product that can do both jobs but maybe I would have to but both. My researche told me that d5 si to use when you have stuff? to flush like an innondation. The D100minibrush would not have flushing capacity but is 20 times stronger.!!! 20 times more concentrated!

4Could someone clarify the use of those 2 products and if just getting the can spray d5 is able to clean the brush contact good enough. If the d100 can only be used on the brass brush area but the d5 can do both the brass brush hole AND be usefull for other parts of the motor let me know which part I would also allow to clean to help me make my choice.

5 For the brush , what parts do I have to clean exactly? All de brass of the hole? The ears of the brush? all the brass of the brush altogether , what about the dark chalky part of the brush should I apply some on it and on its slightly curved part that touches the armature? Is it advised to spray on the copper wire inside the spring too?

6 How do I clean that? is it just put liquid on and let it dry? how many applications? or is it better to take a tiny cloth full on liquid and rub it repetitively on the areas from question 5?

7 What wrong could happen if someone does never apply Deoxit on those parts? Which lead to the question of how often to apply the product. Is it based on how much the motor is used or how much time passes between application?

thanks for you patience
P.S. on top of the brush brass I wrote with a black marker to identify the brush. It is the first part we see when removing the plastic circular cover that protects from water
have a nice day.

 

If the brushes slide into the brush holders without sticking, do not clean them. Do NOT use contact cleaner on the brushes. It could penetrate the carbon brushes and cause them to wear away quickly or disintegrate. Check that the bearings are free and the commutator is clean. Replace the brushes if they have worn down too far to make good contact. That should be the only maintenance that is requires unless you have damage to the armature. If the commutator needs cleaning, it can be done by using a strip of fine emery cloth wrapped and glued over the end of a square strip of wood that will fit through a brush holder. Hold it against the commutator as you rotate the armature by hand.
I recommend that you look up on the internet how an electric motor works.

 

A motor brush is made of graphite (dark part) connected to a metal contact with a copper cable. There is a spring in between so that the brush is pressed against the commutator on the rotor. The entire brush assembly is one electrical conductor.



The curvature at the end of the graphite matches the curvature of the commutator after some time running. Since the shape of the graphite and the hole is rectangular and not square, you cannot make a mistake when installing it.





Brushes do not need regular maintenance. At the worse case, the brush must be replaced when it is so worn that there is little graphite left. Do not use any contact cleaner. Just suck or blow away any fine dust.

Edit: Keith beat me to it.

 

Some heavy current motor applications call for higher mixture of copper content in the carbon-copper brush mixture
e.g. Automotive Starters

 

HI thanks for the answer,
Since we have oil on our hands and that I manipulated the brush brass holder quite a bit, would it be needed to use deoxit on the ears and the place where the ears do contact? Oil is an insulator I think
Also most holes are kind of ok but on the picture this hole has black stuff on most sides. I tried rubbing it with paper toilet dry around a flat screw driver but it does not want to come off.

It might create a problem to have that in the hole is using a stainless brush and apply deoxit on there too a good Idea or a bad Idea.
thanks

 

If you want to wash off contaminants, use IPA (isopropyl alcohol) since it evaporates and leaves no residue. You can also clean the hole with IPA and a small brush. Any other type of cleaner will shorten the lifetime of the motor brush.

 

Why did you remove the brushes in the first place?

 

new used chair, I had to see the state of the brushes to at least do the stuff I can to to verify it is in right order and maximise the chance for it to last longer. Hence the questions about the unusual black stuff question in one of the holes.

 

Your brushes look ok. Just flush out the holes and the brushes with IPA. You can clean the face of the brass looking metal contact with emery cloth and a final wash with IPA.