waterproofing dc motors

i havent tried waterproofing the motors myself..bt have read that it can be done thru silicone..jst google it and ull get a lot of optoins

if you want to go for a household typ remedy,then u can isolate the motor frm the water using a bearing..

keep the motor inside some airtight container(or the body of ur motorboat itself)

place a suitable sized bearing on the wall of the container..connect the bearing to the wall using some good adhesive or mseal etc so that the water does not enter the container where the motor is placed

now,pass the shaft of the motor through the bearing inner ring..select a bearing whose inner dia is jst less than the shaft diameter..so that we have a tight fit..pass the shaft thru this hole(it might take some time..bt lets do it)connect the shaft to the propeller and there u have it..the motor has been successfully isolated frm the water..

u can improve the waterproofing quality bt using some other adhesive(or silicone if u can lay hand on some of it) on the inner ring and the shaft

try this out..it ought ot work..

meanwhile ill continue thinking of smthing else to do this..

Quite impressive!!

thanks a lot!

bt what is a bearing?

a bearing is used to allow for a smooth relative motion between two parts..

generally,the motion transmitted accross a bearing is rotatory motion..

in a ball bearing,a number of steel or ceramic balls are placed between two rings(well the exact assembly is a little more complicated than this..bt this is what it is essentially about)

the outer ring is generally fixed to some support like a hub etc..

the shaft is passed through the inner ring..by using a bearing,u can provide support to a shaft without offering almost any frictional resistance

have a look at the wikipedia article on bearings..that would explain u all

http://en.wikipedia.org/wiki/Bearing_(mechanical)

In motorboat competitons there is no need to waterproof DC motors. They can be directly submerged in water.  

well..wont the motor short if you directly submerged it into water??

No it wont. DC motors are not affected by fresh water.

I had participated in a motorboat competition 3 years back and I had directly submerged DC motors in water for propulsion

you probably are reffering to the fact that fresh water(or rather pure water) is non conducting

BUT.. whenever this motorboat is to be used,we cannot demand pure distilled water...

conections would definitely short coz we cannot have distilled water where we would be running our motorboat 

No no most 12 volt DC motors do not need to be water proofed. The majority will work fine when flooded with water, and if you use them in salt water, just rinse them out with clean fresh water when you are done.

The reason this works is two fold.

First, all of that copper wire in a motor that looks like it has no insulation actually does have a thin layer of varnish or plastic coating. That helps prevent too much current from passing through the water.

Secondly, electricity will always follow the path of least resistance. While water, and especially salt water do conduct electricity, they do not conduct it anywhere as well as copper, so the vast majority of the electricity follows the wires like it should.

Motors that have brushes need those brushes to stay in contact with the "commutator" and the pads of the commutator are not insolated, so water inside a motor with brushes will cause more problems, but it will still work. It's a good idea to stretch or change the brush springs so they apply more force than normal. This will help hold the brushes against the commutator when they are submerged.

hey..thanks fr d nice post..

that means brushless motors would perform really well in water ??

this also means that the method i thought for tim isnt needed at all...such a long reply goes waste atleast fr this simple motorboat 

Yes since brushless motors have no commutator so they will work well.

We appreciate your sincere efforts!

thanks botskool 

i didnt know the solution was so simple

thanks botskool i ll try it out right away

That was a really nice discussions.. but isn't it true that if we will submerge the motor directly in water..it will discharge the batteries soon.. sincce the battery is short when open circuited.. and will discharge very early if there is slightest possiblity of short circuit..

Adi botskool explained it . Current will follow the path of least resistance, and moreover the water being used is fresh water, if at all a salty water is used, still itz conductivity will be lower than copper

OK... thanks for clearing it...

Hey this is the best post that  I had ever seen.... and thnax for making me learn new concept...!!!!

for dis kinda doubts it is always advised to test drive... put a motor in water n run it.. see wat happens... nothing special den use it.. if  any problem arises like sparks, fast discharge of batteries (no need to waste the whole battery.. use a multimeter n measure the current n voltage )blah blah.. don't use dem...dis is how we learn.. how much will u waste?? 35 bucks.. leave it.. if u are new to robotics u gotta know dat 35 bucks is nothing in the field of robotics....

dis was tot by one of my seniors.. thanks to him.. i tried many things, wasted many things but leant much more..

Yes this kind of practical hit & trials will make you learn a lot.. but be careful not to do it always.. always try to aquire theoretical knowledge about that particular thing on which you wan't to work.. this will help you understand its behaviour easily and more clearly...