motor break in?

[canadian-mgt]

I'm taking my first shot at racing 12th scale,so I'm new to electric vehicles.I've read about breaking in motors by submerging them in water while running them at half the voltage that you intend to use for racing.has anyone used this method to break in a motor?are there any other ways to break in a motor?do you even bother? any help is appreciated.

 

[Rolex]

I saw this method demonstrated on Radio Control Hobbies on the DIY channel. It's apparently a good way to do it, since it keeps the temp down, and also flushes the particles from the brushes out as they seat.
5 minutes in reverse, then 5 minutes in the direction it will be turning. Immediately afterwards, you have to thoroughly blow it dry with an air hose, and lube the bushings or bearings.
The absolute best way to get peak performance out of any electric motor is to add a drop of 'Com Oil' to the commutator. It actually reduces the drag produced by the brushes rubbing against the commutator, and increases the electrical conductivity as well.
I've see the amazing difference it makes. Don't run without it.

 

[canadian-mgt]

thanx for the info rolex.I had heard about comm oil before but wasn't sure of what exactly it was meant for,I had assumed it was another term for the oil used for the bushings/bearings.I'll be sure to add a bottle of it to my toolbox.up till now I'd only run 18th scale in electric and we were using the stock hpi motors,so I didn't have to deal with the maintenance involved in using the larger motors.
do you recall whether they had the motor hooked up to an esc or straight to a battery when they did the underwater break in?

 

[Wardo]

Underwater break in is way to funny. The only reason i could ever see doing that is if you were racing a Johnson/Mabuchi sealed endbell 540.


Find or fab up a double motor holder, two pairs of pliers and some elastics will also work.

Face the two arms together (where the pinion slides on) and use some medium fuel tubing to tie them together. One is gonna be a slave, an old junk motor would be fine. It will only be driving your new motor for break in. i use a 4 cell pack to power the slave.

If it's a stock/bushing motor, remove the springs and brushes. Get some Trinity Bushing Buster and follow the directions. After you break the bushings in, clean it well and add your brush and spring combo. Trinity also sells a brush break in fluid but it's not all the great for the comm but will speed up the brush break in period.

Power the slave up again for a few minutes and check how the brush faces are coming in. You'll just need to get them close if you plan on trueing the com.

When they are close, take the motor apart and true the comm, this is huge on stock motors if you are using one.

Once trued and back together, turn the motor with the slave to reseat the brushes, maybe 30 seconds tops. Remove the brushes and add one drop of the comm drop of your choice and it's ready to go.

Remember also, if you do use a comm drop the motor has to come out after every run no matter what. i do it anyway just to knock the glaze off the brush faces but comm drops do leave a burnt residue over the brush.

DO NOT, ever, ever, ever break in brushes or allow a motor to run backwards.

When an RC motor runs, it wears the brushes. The leading edge wears away, the trailing edge (farthest from the motors rotation) does also but at a slower rate. This makes the trailing edge of the brush longer and sharper it it's end. As soon as the motor rotates backwards it's possible to break off pieces of this thin, sharp trailing edge because it has now become the leading edge and is in no shape to be rotated against. This causes arching and alot of other needless stuff.

 

[canadian-mgt]

I appreciate the info,but this sounds a little too complicated.I don't have any old motors to use for a slave because this is my first electric car.there's one thing I don't understand,you say to face the motors towards eachother,but if you tie them together like you said the slave would be turning the new motor backwards during break in.I don't think the local hobby shop has any of that trinity brush break in oil either.on top of those facts,I don't own a comm lathe so I would have to find someone to do this for me.
don't get me wrong your post has alot of good info and I appreciate that you took the time to respond,but it's just too much for someone like me who's just starting out.

 

[Wardo]

there's one thing I don't understand,you say to face the motors towards eachother,but if you tie them together like you said the slave would be turning the new motor backwards during break in.

hey! You're paying attention.


I forgot to add you need to turn the slave backwards, no harm, no foul in doing it to something you're not going to use anyway.

It's not all that complicated, i just tried to give you as much detail as possible.

I'd just run the motor off of 4 cells or around 5 volts if you can. The biggest thing is to get the faces of the brushes seated.

Are you running stock/bushing motors? if so, the bushing buster stuff helps alot. If you can't find it, when you break the motor in do not use any type of lube on the bushings, including water.


Once you lube an oillight bushing you will never get the lube out of it. The hard shaft of the arm will not break off the high and low spots on the bushing and get a polished type surface.

Again alot of details, just think, lubed bushings will not polish. Polished bushings are much faster.


I'd just put a small drop of lightweight lube on the bushings before you put the motor in the car.

Just another tip. Do not buy "bushing lube" for bushinged motors. Buy bearing lube. it's much thinner and worth 300-500rpms on the dyno believe it or not.

 

[scottm]

I have heard a lot lately about under water break in. I do it on small plane motors, like GWS 350C motors. I think it works, I get longer life and better performance from the cheap motors than my buddies. An amazing amount of carbon dust is generated in the water. I have never tried it with a good car motor though, but it should still work. Try searching on rcgroups.com they have a lot of good technical info there.