In the current Backyard Flyer mag Matt Boyd has an article (Goodbye to Gremlins). On page 35 he suggests breaking in your electric motor by running it in a glass of water! Has anyone any experience with this? Sounds crazy to me, seems like it would at the least short the batteries.

http://www.ezonemag.com/pages/efaq.htm#motor

http://www.yourzagi.com/motors.htm

It pays to question what's said in the magazines! Not that this particular item is bad (although I wouldn't recommend it), but on occasion there has been some real bad info passed out. Like you have done, if it doesn't sound right, ask about it.
hoppy

I have done the water break in once. Seems like it did a fine job, but I guess the drawback is you have to really dry your motor well and re lubricate it.

As far as the worry over shorting out a battery it's not a problem. Water itself is a not a conductor. You need a fair amount of ions (think dissolved salts) in the water to conduct electricity, so distilled water (or deionized if you have acces to it) is best for this. Tap water will vary on the amount of salts dissolved in it by your actual water source, so the conductivity will vary as well. Salt water.... don't even think about it.

-chemsurfer

I do mine that way all the time works good ! sounds goofy but does a good job on my 6v s400 planes I break the motors in this way and run 9 cells on them without any problems

I allways break in my Ferrite motors this way. If the manufacturer does not say that the motors are already broke in. I use two "D" size Dry cells (3volts). Let them run for 30 min submerged in water.

You need to blow out the motor with compressed air and the lube the bearings with light oil afterwards. You also should redo it if you change the rotation direction. IMO

Originally posted by chemsurfer
As far as the worry over shorting out a battery it's not a problem. Water itself is a not a conductor. You need a fair amount of ions (think dissolved salts) in the water to conduct electricity, so distilled water (or deionized if you have acces to it) is best for this. Tap water will vary on the amount of salts dissolved in it by your actual water source, so the conductivity will vary as well. Salt water.... don't even think about it.

I break in my car motors this way and I used deionized water thinking of this same reason. The thing is: as the brushes begin to seat, tons of brush particles (on speed600 motors at least) are mixed into the water, which will make it conductive like tap water. At first, the brushes won't arc much if any at all, but when the brushes begin to seat, large amounts of arcing could be observed.

What I have often wondered about is the affect that the water might have on the internal ceramic capacitors that lots of motors have. I doubt that they are waterproof, so I wonder if they continue to be effective.

Anyone ever test one that has been submerged for a while?

Dave

Originally posted by Kidknight
At first, the brushes won't arc much if any at all, but when the brushes begin to seat, large amounts of arcing could be observed.

Boy I'm glad you told me that. I just tried to break in a motor in a glass of water, for the first time, the other day (the Electro Fusion for my Corona helicopter) and towards the end of the process (after about 4-5 minutes) I was getting large amounts of arcing from the brushes and figured that the whole process had been a waste of time (the whole idea is to end up with brushes that don't arc isn't it!) so I took it out, disassembled it and dried it and thought I'd just later go with the "two D cells in clear air for half an hour" method. I hadn't realised that, now dry, I've probably already achieved what I set out to do!

Cliff

Thanks for all the info. Have downloaded a bunch of stuff from various sites. Am going to try the water method on next motor. Had to re-read Kidknights reply when he said he used the underwater method on his car motors. My first thought was how does he find a big enough tank to drop an automobile engine in?

I tried breaking in a Magnetic Mayhem with the water method and experienced the same arcing that was earlier described toward the end of the process. Now I know why!!

My process for the last year is just to put a dab of fine motor oil on the bearings before I start and then put 1 or 2 dry cells in series (depending on the Kv of the motor) and connect to motor making sure of the correct direction of rotation. After the battery(s) run down, spray with your favorite brand of electric motor cleaner, the kind that evaporates quickly with no residue. Then blow out with compressed air. Reoil bearings and continue to clean motor and reoil bearings after every 20 - 30 flights depending on how hard the particular application is pushing the motor.

I was using the 2 dry cell dry method. I just do the same thing in clean water. The times people are seeing arcing is this with two dry cells driving the motor or are you using something more powerfull?

pick up some "break-in" drops at the LHS, (they are for R/C cars) add a couple drops to the comm, run at about half the normal voltage (or number of cells) for about 3 minutes, and you'll be ready to go.

We actually stopped breaking in our 540 car motors, as we reallized that by the end of the 1st lap, the brushes were well seated anyway, and the motor puts out better numbers on the dyno with fresh brushes - we use serated brushes with either a verticle slot, or a small hole in the center. and we rebuild 'em after about 2 nights racing (or after about 8 four-minute runs)

I've heard that you can actually ruin the brushes if you use the water method and go "too long"

Going too long.

I heard the same thing that too long can be bad for a motor. That is why I limit my water breakins to 30 min. on two dry "D"cells.

My understanding of the process is that most of the motors such as speed 400 and smaller have brushes that are cut squarely to the comm with a small surface area in contact with the comm. Water break-in speeds the forming of the brushes by acting as a cutting fluid. 2xD cell break-in takes longer but accomplishes the same thing. Friction is friction.
As far as too long, when you're out of brush you went too long.

Most motors with replaceable brushes seem to have them cut the shape of the comm with max suface area in contact. Pre-shaped and as Kenny said, one lap and the brushes were well seated anyway.
I wouldn't think that water would be good for motors with ball bearings unless you take them out and grease them after a water break-in.

My $.02.

mw