REALLY STUPID QUESTION!!

[XXXER]

Commutator: not commutor, that is what my dad is everyday when he goes to work :p

The spinning armerature in side, has a Commutator, that is made of copper, and the brushes make contact with it, which spools the electricity through it. They occasionaly need to be cut with a lathe.

[IR]

I stand corrected.

BTW, your Dad is a commuter. :P
and it's armature. *My wife's an English teacher* ;)

[Obi112]

WARNING!!! SPELLING MISTAKES A PLENTY!!!
:eek: :eek: :eek:

[Nairb]

Commuter? Armerature? <--LOL! :D

Yeah, the commutator is part of the armature that spins inside the motor can and endbell. It's copper, like they said, and it's the shape of a cylinder (but split into 3 sections). The wires that are wound around the armature laminations are attatched to the comm, and they get charged with electricity when the brushes touch the corresponding section of the comm.

You know, this can be as detailed or basic as you want...

Let me just mention one more thing. The brushes are in direct contact with the comm 95% of the time; they are pushed against it by small springs. Because of the friction between these two (three, because there are two brushes), both things eventually wear down and lose efficiency. The brushes wear down and cut into the copper of the comm. When this gets too bad is when you need to "cut" the comm. This means to remove the armature from the can and use a lathe to cut a new, round, and smooth surface on the comm. When you cut the comm, you should always replace the brushes before running it again.

[Leet TC3]

Replace the brushes every time you cut the comm? Depends on what brushes you use.

Unless you use a REAL (and I mean REAL!) soft brush, you really do NOT need to replace the brushes everytime you cut the comm.

I generally true my comm(s) after 6 or so runs. The brushes I use (AE 767) are always fine, and I don't replace them until they get that "bluish" color or become too short to make good contact.

I think the need to replace brushes as often as you suggest is a carryover from days long ago. Today's brushes are MUCH, MUCH more durable.

Of course, the brush manufacturers will never publicize this fact. For obvious reasons... ;)

[krazymandan]

is it the wire attached to the brush or do i need to take the motor apart to see it!!

does any one have a digital camera or something it would make this alot easier!!

[combones]

The wire to the brush is the shunt wire. Remove spring and remove brush by pulling shunt wire, then look through the brush hood at the commuter? :p :eek:

[krazymandan]

WHAT IS A COMM?? WHAT DOES IT DO?? WHERE IS IT LOCATED ON THE MOTOR??

SORRY REALLY STUPID QUESTION BUT I COULDNT FIGURE IT OUT!

[IR]

Commutor. It's the round copper band at the top of the motor where the brushes make contact. It passes the current from the brushes to the wires.

[losifreak2004]

Leet TC3 - New brushes every time you cut the comm will only help performance. If you don't want that it's OK!!!!

Honestly though, when you cut or true the comm it will be smaller in diameter, and it is always a good idea to use brushes that weren't seated and run on the comm when it was a different size

KrazyMandan - I just figured out your name LOL. Take off one spring and slide the brush out of the hood, and look through it, just like combones said LOL

[Leet TC3]

I disagree. The notion of needing to replace brushes everytime you cut the comm comes from long ago. Motors ran a lot hotter, and the material of the brush was entirely different from what they use today.
Not many racers had lathes, so by the time they got their comms cut the brushes were in BAD need of replacement.

This notion has been passed down and parroted since then, giving little thought to the realities of today: You don't need to replace your brushes unless they are very worn or have turned an odd color.

If your old brushes won't seat well with the fresh cut comm, how can putting NEW brushes in make that situation any better?

When you cut the comm, you are taking micrometers of metal off, and you are (mostly) keeping the identical shape. So your old brushes should still be perfectly seated on your cut comm. If you put new brushes in, you will have to take the extra step of breaking them in, and THEN cutting your comm again because this break in process will cut into your comm.

You can go ahead and replace your brushes everytime you cut the comm, but imho it is a huge waste of money and time.

[IR]

I just don't get why you wouldn't change the brushes. They are old, used and not as effective at transferring electricity from the ESC to the Comm as brand new ones would be. Besides that, they are what, a couple bucks? If you are taking the time to turn a motor, than a couple bucks investment in new brushes seems like a given.

It strikes me as being the same as taking a shower, shaving, brushing your teeth and putting the old nasty skivvies back on. It don't make no sense!

[Leet TC3]

Wow Idaho, that's how I take a shower, don't you? :)

I true my comm's weekly. All of them are soldered to the endbell. Sure, it only takes a few minutes and few bucks, buy why bother?

I disagree with your contention that the old brushes won't perform as well as the new ones. Both on the track, and any dyno readings that I am aware of, the "used" brushes suffer no perfomance decrease as long as they are not too worn or abused.

I have no problem with people who do it, just as long as these aren't the same people who complain about the expense of this hobby. If I were to change brushes every week, over the course of the year I would spend over $150 on brushes alone.

[noobie]

theoretically, old brushes are shorter, therefore creating a shorter distance for the current to travel, therefore creating better performance.

if big jim and jim deiter and guys like that don't change their brushes whenever they turn a comm, I am not going to. Especially if I have those brushes aligned right, narrowed just right, already soldered on the endbell, etc.

[combones]

ditto :D

[bryceanator]

ah crazymandan the only stupid question is the one that isnt asked

[krazymandan]

ahhh yes master

[krazymandan]

now where on the comm do i put the comm drops(team orions speedy drops pro)? does it matter?

[ProjectTwin]

SO, where does a brush-cutter come in?

Teach me something about electrics guys. Unless it's a stock 540, I don't know much about it. That's part of the reason I never persued the R/C Drag racing much.

Jason

[XXXER]

Dan: Just look for an opening, that you can fit in the little deally, and only put ONE drop in there, just enough to coat the comm.

Jason:There are Brush Cutters, Slotters, and Serrators. Cutters are to shorten the brush, mainly for Reedy's Big Comm motors, Slotters make a vertical slot, for increased RPM's, Serrators give them the look when they were new, for faster break in.


YOU CAN USE OLD BRUSHES, after a comm cut, Just that i do not, heck, 3 bucks, is no big deal over here :rolleyes:

[ProjectTwin]

After cutting the comm, couldn't you just tap the brush on a cutter and run-in the motor again? As long as you don't make an excessive cut on the brush you should be good right? Just enough to cut the face of the brush?

Jason

[XXXER]

Jason, that is right, and many people do that, if i had a slotter, I wuold do that! But, seeing as I do not, I am not very worried. hehe. But, after they get too short, then they stop making contact with the comm