Running motors under water

[marvin harten]

Has anyone tried to run 12v dc motors under water after treating them with "Stuph" or "Corrosion X"? If so, what were the results? Did you see any corrosion or malfunction? Any information would be appreciated. Thanks.

[raalst]

I ran a 6v dc

I ran a 6v dc motor with only a dose of silicone spray.

I ran it twice in a chlorinated pool, once in sweetwater,
and it still runs normally (it is a year later, I am rebuilding but
that does not include replacing the motor.
omly corrosion I can see is in the power lead soldering joints.

I use motors from electric door locks for cars. nothing special,
cheap and probably replacable by same for a couple of years.

mind you, getting current thru a WTC end cap is a lot simpler
than getting a sealed rotating axle through.
and it saved valuable WTC space.

go for it !

have a look at My Webpage



Edited By raalst on 1141164029

[bob the builder]

I've been thinking about building

I've been thinking about building an electric torpedo with some small pager motors that I happened on. Sealing these little motors without binding the shafts with seals has been perplexing me a bit.

Ideally, I'd just saturate the motors in oil and let them run wet. Fresh water shouldn't pose a problem, should it? A quick spray with a water displacement spray like WD-40 after each run should keep them shipshape, shouldn't it? It'd sure save a lot of headaches and simplify the whole process....

Any thoughts?

[raalst]

i think you are right.

i think you are right.
just be prepared to change the motors
a bit more often (i.e. they will last a bit shorter).
and check that the motor type you use is likely to be found
again when that moment of replacement comes.

in the spirit of advancing the hobby, give it a try & report on it.

btw, most oils have a high resistance and do not interfere with
electronics. ROV motors often are embedded in oil to make it easier to counter the water pressure (by oil pressure, instead of air).
(pure) fresh water also has a high resistance, which goes down with pollution levels.
chlorinated water (public swimmingpools) does conduct a bit more, but it never hindered me.

However, more conducting means more corrosion. be sure to rinse the boat/torp with fresh/drinking water after use in chlorinated water.

hope this helps !

ps
public pools might not be won over with oil filled subs, though.
so it depends on where you aim to play with the boat



Edited By raalst on 1141250333

[bob the builder]

Almost sounds too easy to

Almost sounds too easy to me. Just waterproof an AAAA battery, tie it to a little motor through a small reed switch, and you're done. I'll have to play.

Sounds like an article for the SCR to me...

[Guest]

Bob,
Lot's of luck with your

Bob,
Lot's of luck with your electric torpedo idea. I didn't have much luck with a 1/72 size torp, using a micro car motor, hearing aid batteries, and a reed switch. I like to keep things simple, but I didn't get enough torque with direct drive, to run the prop in water, and I gave up.

[bob the builder]

Art,


My torps are going to

Art,


My torps are going to be in 1/48th scale, to go with my 1/50th Victoria Class sub. Makes for about 1/2" diameter on the torp and about 5" long (I think). I found some dandy little pager motors that look like they'll work just fine, but I'll need to play a bit first.

I'll take a closer look at everything in the next few weeks and post some progress here when I learn something.


Bob

[bill marks]

First, if you choose cheap

First, if you choose cheap motors and run in fresh water and you have to replace them after each outing, so what? I can buy a lot of motors for what a good shaft seal cost.

The biggest problem running cheap DC motors under water is the water whirling arond inside of the motor quickly erodes the varnish on the windings and fatiques the brush holders. The load on the motor wil be higher due to the water resistance around the rotor inside of the motor casing.

Make the motor easy to install and remove and the setup fairly universal so if you can't get the exact motor replacement onr that is close in size will work.

After running underwater in fresh water, drain the water out of the motor and flush the internals with WD-40. Run the motor in air for a few seconds to make sure as much of the internals as you can get coated.

Don't use a motor that has an internal fan like some of the Johnson Controls motors. It really increases the rotational resistance of the motor under water.

If you run in salt water, a DC motor very quickly becomes inert ballast!

Bill

[locoworks]

Gentlemen
Water in self is a

Gentlemen
Water in self is a lubricant, but not as good as oil

1 wd40, rp7, etc are listed on the can as water displacing!
It also means they displace/ break down the oil as well which is not good.
Try to keep the sprays away from the bronze bushings or whatever the motor uses as bearings.
After running wash with fresh water, spray internals of motor with wd40 if you must, I prefer dry in the sun, and then oil the bearing surfaces.
You only need a small drop of oil on each bearing, apply with toothpick while motor is rotated slowly after each run.
re the armature windings I have never seen a enamelled wire breaking down due to water resistance while in use ( cavitation may be a player here but?) again the main problem comes from the water displacement sprays breaking down the protective covering on the windings, as they can soften the protective lacquer coating.( i think they also warn against use on painted surfaces)
Tony Sth Oz

[carcharadon]

Has anyone tried to run

Has anyone tried to run 12v dc motors under water after treating them with "Stuph" or "Corrosion X"? If so, what were the results? Did you see any corrosion or malfunction? Any information would be appreciated. Thanks.

You could try a bilge pump motor. A 500 gph 10 bucks real cheap.

http://www.shop.com/op/~Johnson_500_...-prod-13749896

[cyclops2]

How fast , or slow,

How fast , or slow, were the USN WW II sub torpedos in the early years ?
I to am trying the electric torpedos.
I need a figure to scale down to FPM in model sizes.

I ran out of parts for a timer, to control the total torpedo running time. Only could do 2 seconds. More parts ordered for longer runs.

[cyclops2]

Stumbled on to a site

Stumbled on to a site with setting the speeds of the 21" as being, - slow, 32 knots - fast, 47 knots.

Does that agree with actual speeds ?

Rich

[mermaid]

The thrusters used by the

The thrusters used by the deep diving research subs are light oil filled units. Why not run the motor in a sealed can filled with oil? I imagine this would work best with lower RPM motors especially if brushless.