Importance of Motor Maintenance
 

Well tonight I figured I would rebuild a couple Comp motors and my practice motor. Being old school Im one of those guys who only run Brushed motors and needing speed still I only run 30 and 35 turn hand wound motors but for my test and tunes and just farting around I have a 35T Integy motorthat I use.

Well my 30T and 35T comp motors went easy. Turned the comms, reseated the brushes and spun them up just to see if they were maintaining their power like before. That was the easy part.

Now came the practice motor, this thing is basically stock motor that all i did was align the hoods and stick some special brushes in. I never even touched the comm before tonight.

I have to say in 15 years of building many different types of motors for all sorts of racing at both little and big type events I have Never seen a comm this bad so I thought it would be a good thing to post and show how important maintenance on machine wound motors can be. This isnt to say Hand wound motors dont need the same touch of love.

Heres the Comm after 8 passes on a Cobra Mod lathe with diamond bit. 1 pole is clean likeit was never run.

http://i208.photobucket.com/albums/b...DSC00242-1.png
http://i208.photobucket.com/albums/b.../ADSC00244.png
http://i208.photobucket.com/albums/b.../ADSC00245.png

You can see that 2 out of the 3 poles werent even touched yet but the bit, this thing was seriously out of round.

Heres another 7 passes

http://i208.photobucket.com/albums/b.../ADSC00246.png
http://i208.photobucket.com/albums/b.../ADSC00247.png

you can now see where the brushes were just jumping on the 2 poles arching the crap out of them. ( the deep pits indicate this )

5 more passes and I finally got the brush groove to show

http://i208.photobucket.com/albums/b.../ADSC00248.png
http://i208.photobucket.com/albums/b.../ADSC00249.png

6 more passes and all 3 poles were finally clean

http://i208.photobucket.com/albums/b.../ADSC00250.png
http://i208.photobucket.com/albums/b.../ADSC00252.png

I have built hundreds of hand out race motors at Trophy/National events for many years and even those have never started out or became as bad as this thing. Im not saying all machine wound Integy or other brands are like this but figured Id show it as an example.

Just food for thought, the next time you think about submerging your scaler or it feels like your 2.2 stalls at the wrong time, you may just want to ask yourself when was the last time you inspected your motor.

Show that thing a little love every now and then and always maximize the performance in it.

And if possible and in the budget when needing a new motor ........ try thinking about one of those Hand wound motors the vendors here offer. Not saying it cant happen to them too but atleast with those there is a little piece of mind that its not just thrown together quick to meet a piece count for the day.

Hope this helps someone ......... "thumbsup"

Awesome post Robbob "thumbsup" Thanks for the detail and great pictures "thumbsup"

That's good info, thanks for sharing.

One question...what about hand wound motors means the comm would be straighter? I don't see how this being a machine wound motor would automatically be the reason it's not running true. Is it because hand wound motors start with a better quality core, and are trued prior to winding?

I don't know jack about hand wound motors, obviously :) Skool me.

Absolutely, Hand wound motors can be the same way. Sorry if I made it sound like they couldnt.

The difference though is a hand wound motor done by known vendors/companies that specialize in this field tend to have some one who checks and trues the comms after they are wound, epoxy baked and balanced.

The companies who do these machine wounds in bulk just pull wound arms off the machines, throw them on a balancer, drill a couple holes and wipe some thin based epoxy on the wires to hold them together.

They dont take the time to true comms or even check them, big reason why a machine wound costs 19.99 and a hand wound costs 40+. Its like buying a big screen TV from the guy who sells grinders, milk and candy bars or buying one from someone who specializes in Electronics. You can get a heck of a deal but how good is it really gonna be. :lol:

I assume the big factor that can cause what I saw is the machine that bends the comm tabs over the wire, it either tweaked the comm or was just plainly mis-aligned.

I know my integy 35ts are in need of trueing. But I don't know anyone with a lathe.:-(

hey there

Great write up. I trued a 55 turn recently and had a very similar looking comm. I was actually not sure how it was possible for the motor to spin evenly and make power at all.

I have a couple questions;

1. What is the min diameter you can have on a Integy lathe motor (I think 6.9mm???)

2. What are good replacement brushes for a lathe motor? (a link would be great)

3. What does hood alignment do and how do you do it?

Thank you

1. we use to peel stock comms @ 0.267 inch ( 6.78mm i believe )

2. Reedy Quasar's - Reedy 767's - Trinity E-brush - Trinity Silver Serrated - Putnam Propulsion

3. Hood alignment helps the brushes contact the comm evenly and adjacent to each other. There are several tools out there that help you do this.

http://www.racers-edge.com/Centerlin..._p/rce7040.htm

Nice post. "thumbsup"

I have been cutting and building my own motors for about a year now using an Integy X-Mod lathe. Im still learning but it has been a lot of fun.
http://i20.photobucket.com/albums/b2...g/IMG_0112.jpg

Im using the Carbide bit supplied with my lathe. Would you recommend the diamond bit?

I just ordered the Brush alignment tool. Thanks for the link."thumbsup" Do you recommend any other motor building tools??

So then what is the best motor maintenance advice? Try to keep the brushes clean, maybe blow them out each time after running the car? Do they need lubrication of some kind or just leave them dry? Or just take it apart and true the comm periodically-about how often?

thats why i cut the comm of my cheap motors before the first run :lol:

I do the same as well. I have had the same experience with my 20$ integy motors :lol:

http://img.photobucket.com/albums/v7...noclone013.jpg

http://img.photobucket.com/albums/v7...noclone015.jpg

http://img.photobucket.com/albums/v7...noclone011.jpg

http://img.photobucket.com/albums/v7...noclone018.jpg

Its amazing how out of round these things are, its also amazing what a difference in performance there is when you have a nice trued comm, good brushes, and some stronger springs.

Word to all that.

About a month ago I did 5 motors and they were all cheap Integy motors. A company should be embarrassed to put something like that out on the market. :ror:

I had to take quite a lot off to get it round.

looks like we use the same lathe too "thumbsup":lol:

I would always recommend a diamond over a carbide but if yours is aligned and still cutting clean id say keep with it. If you start noticing a dull finish or vibration lines in the comms then it might be time to upgrade.

Comm sticks are good to have too for those in between cleanings when you just want to clean the comm lightly, no deep grooves, and fir cleaning brush faces.

For crawling I wouldnt think of adding any chemicals to the brushes, its just gonna make the dust collect. My opinion would be if you run frequently give your motor some visual inspection. If you notice the comm becoming discolored then it may need a good tear down and turning.

Brushes are easy inspections, is the face or edges discolored? are they wearing on an even arc or does it appear to have a tailing edge to it? are they almost worn?

If your a scaler that runs in dirty, muddy or water style enviroments often then you would want to inspect your motor more often.


I remember when we would complain about the blue end bell Trinity handouts because the magnets sucked or the wires were wound loose, never had a comm like these though. Cleveland one year Trinity had a rash of handouts come through with the magnets in backwards, the directors told everyone who got one to find a motor builder with a magnet zapper and zap them backwards. :roll: I didnt know what was going on untill about 10 guys showed up asking to get theirs zapped backwards, we got a good laugh at Trinity's expense that year.

Brushed motors really do take a lot of work to keep running smoothly. I would like to add that about 7 degrees of advanced timing on a normal three slot motor will save the comm a bit. It will have less arcing in forward locomotion, and less pitting between the comm segments.

As much as I love brushed motors, the ONLY rig I have them on now is my 1.9 and 2.2 comp rigs. Everything else runs brushless.

"thumbsup" Thats good info.

I put up some info about timing and such in this thread http://www.rccrawler.com/forum/holmes-hobbies/125790-caring-your-new-brushed-motor.html

Because I am admittedly lazy when it comes to motor maintenance and I do not have the proper tools (lathe, comm stick, etc) for a brushed motor, I run brushless in everything"thumbsup". This is a great thread by the way though.

If yer after an alignment bar, here is the one I had made, designed by Big Jim Greenemeyer.

http://www.teambrood.com/catalog/pro...roducts_id=715

And just for the record, NO company trues the comm after balancing. We all do it right before, cause if you don't, the arm will not be in balance after the comm is cut. It is cut to be perfectly round at this time though.

The super cheap motors use a really cheesy comm setup. Typically when it takes a ton of cuts to get round, it cause the comm has shifted from either the copper expanding or worse yet, the glue getting hot and moving. The better armatures you see in the top end handwound stuff use a better glue and a higher grade of copper.

.270 is the SAFE point on small comm arms......anything less is playing with fire, but is probably a bit safer in crawling, as the motors are not spinning at 20k RPM.

I would advise against comm drops of any kind from crawling. They really only work well for one run and then the motor needs to be redone.

Moral of this thread.....quit buyin $20 motors to put in your $200 axles.:lol::ror::-P

Later EddieO

Very nice write up,looks like im going to have to check my motor and see what it is like.