Are motors really water proof?

so i am working on an underwater rov. im making progress, but when i search online for tips on water proofing both brushed and brushless motors, people say that they are allready water proof. i dont want to test it without checking with the forum. if they are not water proofed any tips would be appreciated.

What motors?

2 NEEWER Emax CF2805 2840KV 29g Micro Outrunner and dc hobby motorshttp://www.amazon.com/NEEWER%C2%AE-CF2805-2840KV-Outrunner-Brushless/dp/B00FLI5EQQ

I see lots of large holes in the casing for that motor that will let water in. How could you even think it was worth asking the question.

The simple assumption is that no motor is waterproof unless you can find one where the manufacturer has specially designed it for that purpose. If you can afford it, it probably isn’t waterproof.

Although it is off-topic, electric motors seem to work quite happily when immersed in a non-conducting and non-corrosive liquid - including petrol (car fuel pumps).

…R

So, the answer is no. so I'm going with drive train

Never heard of a water proof motor other than the submersible aquarium pumps. Water + DC electricity = electrolysis = dissolved wiring.

Ok thanks.

A brushless motor will work underwater but I'm sure you'll still have dirt/corrosion problems over time. If your motor uses ball bearings then those will rust up as well; you would need to replace those bearings with brass bushings.

MarkT: Never heard of a water proof motor other than the submersible aquarium pumps. Water + DC electricity = electrolysis = dissolved wiring.

The coils and lead wires are all insulated. He might have problems at any uninsulated solder joints, and it would probably be a good idea to add a few extra layers of some type of conformal coating to the stator, but other than that, why would there be a problem with electrolysis?

Check out what these guys are doing re: potting BLDC motors:

http://hackaday.com/2014/01/18/0-19-leagues-under-the-sea/

Some motors can run in liquids, depending on if the liquid is electrically nonconductive, or all electrical parts are insulated from the liquid. Frictional power loss running in a liquid can be an issue. Some ROV projects get stumped trying to seal the motor drive shafts if the motor is in a compressible gas atmosphere. One approach might be to run the motor in an appropriate (and generally non compressible) liquid so there is no significant pressure differential across the motor shaft seal.

Chagrin: A brushless motor will work underwater but I'm sure you'll still have dirt/corrosion problems over time. If your motor uses ball bearings then those will rust up as well; you would need to replace those bearings with brass bushings.

Dear me, what a bad idea!

A common tunning technique for stock brushed motors in RC Racing is to running them on low power for five minutes submerged in a glass of water. Look up 'water dipping motors' - essentially the water acts like an abrasive to bed the carbon brushes to the commutator and generate a little more power, it may also have a similar effect on the brass bushings that act as bearings in low cost stock motors.

Example here - http://www.rcuniverse.com/forum/rc-drifting-304/5583008-how-water-dip-new-motor-10-step-guide.html

Outside of breaking in a new racing motor which has a short life anyway, its still a bad idea.

Duane B

rcarduino.blogspot.com

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