Mobility Scooter and Power Chair PartsPowerchair (Power Wheelchair) MOTOR BRUSHES! Detailed Full PowerChair Related ONLY Menu HERE Obviously in a reasonably new Powerchair, there is no point in checking or replacing the Motor's Brushes, unless you do actually have reason or suspect a problem. They will likely not be worn or faulty or burned unless you are very very unlucky!  And most likely your chair will still be under warranty anyway. If its not, and you have a fault. for e.g. if the Motor "stops" one one side intermittently or for the first time. Or if the Chair starts to pull left or right intermittently. Or if it's making a "Strange" newTHEN you need to check. Motor brushes are made from Carbon (mostly, but a mixture of carbon and other materials) and they are very soft. You can scrape, file or sandpaper the brush material away very easily. It just makes a pile of carbon dust, and if you try this and then you need a new one! 

It also makes it trivial in an emergency to fit the brush from a current powerchair into an old no longer made one that parts are unavailable for. A little careful selection, and a file and it can be done. Brushes transfer the POWER (from your batteries to the motors rotating internals. They do this by riding on a segmented copper thing called a This it the part that spins inside your motor and that the Motor's brushes (that we will be examining) run on. A spring provides some pressure. free to move as they wear to maintain contact. They provide up to 120 amps of power in a modern powerchair to this copper "ring". Usually the faster / bigger Powerchair has 4 brushes on eachIts called a 4 pole motor. Smaller powerchairs use 2 pole motors which tend to eat brushes faster in my experience.One is shorter than the other due to wear/arcing and use. All four from this motor were the same, The longer one is a NEW one shown as a comparison. 

You need a new one to compare the length. These though are actually from two different "years" of the same motor. The cleaner and longer one is the replacement.  Also examine the "tip" for burning, and chips or bits missing Obviously the shorter one is absolutely knackered here! I check and swap mine asWorn brushes eventually cause breakdown, and damage to the armature from arcing as the spring pressure is then too low. "run in or break in" they "wear" and conform to the curved shape ofActually they more "burn in" to begin with due to the small contact area of the new "square" ended brush. So it pays to go steady and avoid heavy loads like ramps and hills for a few days with a new powerchair. you have the patience! When new they are generally just square ended like the new one seen above. But once bedded in they have a "curve" that the commutator (WAY above!) as you can see in this close up picture below. all the tiny grooves in its surface match too.

The commutator also wears as it runs as well but does so much slower. This brush  below is perfect with no burning (arcing) or any real wear or other damage or chips or pits.  Pits and chips actually happen due to arcing as these things have a very large current going through them at times depending on chair and user! Its just 5mm shorter than the brand newback jack chair assemblyIf it was 8 to 10mm shorter it would go in the bin. bean bag chair south africaIt can only go into the motor one way due to the design of the brushcheap ergonomic office chairs ukIt fits into a rectangular slot, (below) It therefore sits in "exactly" the same position (as it should) as it did before it was everIt cant really do any other.

This one will go back in as its perfect. motors it is possible to replace the brushes in "reversed" and although its not that detrimental, it's still best to make a note of which one went where and its orientation . Its because of those tiny grooves you can see and the exact angle of the "worn in" end.  If you get it wrong it will soon "wear in" again regardless as its soft. You will not notice any "wearing in" takes a very small amount of material away and shortens the life aLikely you wont care once you see how easy they are to swap and they are continue to wear / burn away slowly throughout the life of the powerchair . Brushes are like brake pads for your car, they are considered as items that areThat's why your powerchair manufacturer carries these as a spare and why you can swap them in minutes in situ. generally good enough to last many thousands of hours with an average user on with average programming . that's you and you have a quality branded powerchair with no odd noises then

don't bother checking them for about 3 to 4 years! you have a some attitude , do Powerchair basketball, football, etc. And if you REALLY USE and hammer your powerchair to the extent that a set of batteries will last you about a year or less then check them yearly! And or you do hills, ramps, off road, winter, and especially if your chair is programmed to get the most possible out of it then it also pays to checkYou see not everyone is the same. my chairs are about half worn after 12 months of the kind of daily abuse I give them... If this sounds like you it would pay to remove the brushes (takes just minutes on many powerchairs) and to examine them. manufacturers see no problems with brushes since the average user sits about, doesn't go off road, on beaches, or discharge a set of batteries almost completely every single day.  Normally they sit at a desk, or at a computer all day, or in front of the fire. If they do "go out", they are not aggressive and do

it only a few times a week and don't go very far.  do USE yours , then you are outnumbered by about 1000 to 1 and considered an aberration!  You are not part of their figures. You do not need to was just an old dead abused 2  pole one that was going in a "robotic" vehicle. them to check condition BLOW ALL THE CARBON DUST OUT!  You will get a cloud of horrid I got several egg cups full out of this old 2 pole motor! That dust gets into bearings and the motors windings as the whole internals are sat in a pool of it!  so much in this motor it sounded weird... the end off like this! use an airline in the positions where the brushes were to If the powerchair is correctly designed (amazingly some are!) you will be able to remove 2 or 4 caps from your motor casing to access the brushes in just a couple on minutes in place. Its really simple and if nothing else, it gives you some peace of mind. Or shows you how fast they are actually wearing in your

The tag in the centre of the photo is where the motor wiring loom plugs on. Some are different and have a cable emerging from the motor and a screw cap rather than a sliding one. (see end of page) Here that square plastic thing just slides out as below to reveal the brush... There are 4 obviously on this motor. Slide out like this (at least on this motor...)That took 2.5 seconds and about 5 mins to find the camera Brush just lifts/pulls out. But not a waste of time since these motors were sold to a friend. to sell a set of motors to someone without knowing they are still good to go! I also blew out all the dust, checked the bearings, the gearbox backlash and the Cush drive/motor coupling while I had chance.  And tested them on a Needs the dust blowing out, the brushes wiping on a cloth (they were coated in dust that made them not slide freely as they areThen put all 8 back into both motors IN THE SAME POSITIONS, AND THE SAME WAY AROUND as you took them out.