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mackey
04-27-2007, 02:07 AM
Hi,

I have broken in brushed motors by running them submerged in water. However, I'm concerned about flying a brushless outrunner in light rain. Would flying a brushless outrunner in the rain be a problem?

Bill

Saucerguy2
05-01-2007, 08:28 PM
I've never heard of such a thing about running a brushed motor submerged, I'd think you'd short it out immediately. I wouldn't reccomend flying anything in the rain.

Grasshopper
05-01-2007, 08:38 PM
I've broken in all my brushed motors in water. I would be more concerned about water getting in servos, receiver and ESC.

Balil
05-01-2007, 09:25 PM
if you float fly usually you waterproof everything. i flew my stryker in a light misty rain and havent had a problem from it yet.

jdetray
05-02-2007, 05:26 AM
I've never heard of such a thing about running a brushed motor submerged, I'd think you'd short it out immediately.
Water breakin is widely used for brushed motors -- has been for many years. Click here to read about it. (http://www.rcgroups.com/forums/showthread.php?t=201081)

- Jeff

r_kopka
05-02-2007, 09:50 AM
Motor is no problem (besides the ball bearings). Motor wires also not, but be careful with the ESC itself, especially small drops at the power FETs are dangerous. Usually closed fuselage should be enough for a light rain. Waterplanes (as mentioned) are a different case.

RK

Saucerguy2
05-02-2007, 10:11 AM
Sorry, haven't clicked the link posted here, I'm going, water is an excellent electrical conduit, the motor requires a positive and negative, crossing them with water means it's going to short out.

I'm learning something here guys, it's really strange since this contradicts what I've been taught and experienced first hand, but I'm keeping an open mind should there be some quantum factor involved that I have not learned of, so far, I remain skeptical and will NOT submerge my brushed or brushless motors under water, well... unless they are waterproofed and you guys can back up with replacements if you are pulling my leg.........

That said, there is zero reason to break in any electric motor, it's not the same as a gas one at all !!!

TRASHBUG
05-02-2007, 11:35 AM
Brushless motors will run just fine underwater provided you don't have the airplane prop on them at the time:)

Really nothing to go wrong here except rusting.

Actually, pure water is a very poor conductor of electricity. The more impurities you have in the water the better it conducts. Of the "water" normally found laying around, salt water is the worst. Not only a conductor but corrosive to boot!

There's an interesting product that others have used, with good results, to waterproof their rc stuff. It's called Corrosion X (http://corrosionxproducts.com/?gclid=CJeXhKml74sCFQUOIgodaTmOQw). There's a fair amount of information in the different RC threads. Experience has been generally very good.

LOL

smokejohnson
05-02-2007, 11:40 AM
I remain skeptical and will NOT submerge my brushed or brushless motors under water, well... unless they are waterproofed and you guys can back up with replacements if you are pulling my leg.........

That said, there is zero reason to break in any electric motor, it's not the same as a gas one at all !!!

LOL, I have never done it but I have read plenty on it. It CAN be done no problem. After you dry it out I think you should put a couple of drops of oil on the bearings. I'm not sure exactly what it does but it is for the benefit of the brushes, so I don't think it would be needed on a brushless.

Grasshopper
05-02-2007, 02:25 PM
Breaking in a brushed motor in water does no harm to the motor whatsoever as long as it's done properly. I use distilled water. DO NOT run a brushless motor under water. There is no need to. The reason for doing this with a brushed motor is to allow the brushes to wear in to the shape that matches the commutator. Doing this under water reduces the arcing and pitting of the brushes while providing some lubricant and cooling.

You will want to dry it out with a hair dryer or heat gun and add a drop or two of sewing machine or 3 in one oil to the bearings. Don't use WD-40. By dong a water break in, you extend the life of the brushes and therefore the life of the motor.

Saucerguy, we're not pulling your leg here. I have done it with all my brushed motors and have never had a problem with it. Here's a link to the process. Go to post #47 http://www.wattflyer.com/forums/showthread.php?t=8384&page=2&highlight=water+break+in

Bundy_90
05-02-2007, 02:44 PM
Motor is no problem (besides the ball bearings). Motor wires also not, but be careful with the ESC itself, especially small drops at the power FETs are dangerous. Usually closed fuselage should be enough for a light rain. Waterplanes (as mentioned) are a different case.

RK
So you could seal it with hot glue?

jdetray
05-02-2007, 04:34 PM
That said, there is zero reason to break in any electric motor, it's not the same as a gas one at all !!!
The reason why you might want to break in a brushed electric motor has to do with the shape of the brushes versus the shape of the commutator.

In a new motor, the ends of brushes are usually flat. The commutator of course is round. A flat brush resting against the round commutator means there is only a very small point of contact between the two. Motors run better when there is more contact area between the brushes and the commutator.

To increase the contact area, you break in the motor by running it for a period of time at low voltage. This slowly and gently grinds down the brushes until the ends of brushes conform to the round shape of the commutator. This is known as "bedding in" the brushes.

Performing the break-in under water is said to be easier on the motor than doing it dry. The water eliminates arcing between the brushes and the commutator and thus reduces the chances of pitting. The water also helps to carry away the small particles that are removed as the brushes take on the desired curved shape. You'll see the water become discolored as the tiny particles of brush material are flushed out of the motor.

We used water break-in 40+ years ago to improve the performance and longevity of model train motors. Then the slotcar folks started doing it, followed by electric R/C car and aircraft folks.

Here is some additional information about water break-in for brushed motors.

http://www.rcuniverse.com/forum/m_5628228/tm.htm
http://www.ikarus.net/forums/showthread.php?t=36366
http://www.ezonemag.com/pages/faq/a415.shtml
http://barnson.org/node/777 (scroll down to item 3)
http://www.rccartips.com/rc-electric-motor-tuning-guide.htm

To be fair, there are many who are of the opinion that dry break-in works just as well, though it may take longer. And some folks don't think it's even worth the trouble to break in cheap brushed motors. Still others will tell you that it's the cheap motors that need breaking in most of all!

- Jeff

giflyrc
05-02-2007, 04:53 PM
Just think, you would be standing out in an open field with a-------

LIGHTNING ROD IN YOU HANDS!!

Roger aka GIFLYRC

Saucerguy2
05-03-2007, 03:12 AM
Well, I guess I learned something new. Thanks all.

r_kopka
05-03-2007, 09:21 AM
So you could seal it with hot glue?
That's one way. I use a second thin heat shrink tubing and seal the ends with a ( e.g. bathroom) sealing compound before and during the shrinking. It should be something flexible or the wires will move and break the sealing.
But be careful with warming during use. This seal will also lead to a worse heat dissipation.
A fast way is a balloon over the parts (also RX) tied up with rope or tape. Same problem with heat. My SuperZoom 25A ESC will shut down after about 4min packed in a balloon, while it works longer without the ballon.

To break in of brushed motors

- destilled water is not necessary. After a short runtime the water will be dirty and the effect is null.
- the currents through the water are some decades less than the motor current. There are some divers who even use open systems for lighting. I.e. batteries and halogen bulbs are not isolated in the water - of course only in fresh water.
- I fly Pylon400 and we MUST break in all Speed400 motors or they will either run much slower or much shorter than a motor broken in. A motor with break in can last for a season without loosing power and we don't treat them well (10-13A for 4min).

RK

Dr Kiwi
05-03-2007, 07:13 PM
Sorry, haven't clicked the link posted here, I'm going, water is an excellent electrical conduit, the motor requires a positive and negative, crossing them with water means it's going to short out.

I'm learning something here guys, it's really strange since this contradicts what I've been taught and experienced first hand, but I'm keeping an open mind should there be some quantum factor involved that I have not learned of, so far, I remain skeptical and will NOT submerge my brushed or brushless motors under water, well... unless they are waterproofed and you guys can back up with replacements if you are pulling my leg.........

That said, there is zero reason to break in any electric motor, it's not the same as a gas one at all !!!

Brushed motor are better if broken in - it is done to contour the square brushes to fit the curve of the comm.

If you don't believe that brushed motors can run under water - you need to tell that with every farmer with a submersible well pump - they are not sealed, yet run fine for year after year! [We use one in an artesian well on our summer island in Maine to supply water to the community].

Bill G
05-08-2007, 07:04 PM
I think the thing that is often misunderstood is the voltage here. I wouldn't break in a 110VAC industrial motor in a bathtub!:eek:
At 12V, the water's conductive property does not cause a problem. If you added an electrolyte, such as salt, that may change things, but then again, it would rust the motor too, and would not make any sense to do.


If you don't believe that brushed motors can run under water - you need to tell that with every farmer with a submersible well pump - they are not sealed, yet run fine for year after year! [We use one in an artesian well on our summer island in Maine to supply water to the community].
Yep, a little carbon brush in the drinking water never hurt anybody.:D

Bill

foxtestpilot
10-12-2007, 05:22 AM
i was told to break my brushed motor in water too .. weird huh