I need help with brushless motors as thrusters

[Erik102696]

So I'm part of the mate competition and looking forward to next year I want to use brushless motors. But the issue has come up with waterproofing. My coach says that they need to be waterproofed and I say they don't. What do you guys think do they need to be water proofed. They will be mainly working in a chlorine pool. Also if they do need to be waterproofed how would that be done? Since they are out runner motors you can't have the housing be up close to the sides of the motors. So I guess my main question is if they even need to be waterproofed and if they do how would you go about waterproofing?

[jpWA]

I would agree with you that you don't really need to waterproof. The conductivity of fresh water even with chlorine is so low that it will sap a negligible amount of current from your motors. However, you should probably wash the motors with tap water after running your ROV in the pool to prevent any corrosion.

[sthone]

I think your coach is be right.... only because I'm pretty sure the MATE rules say that all electronics and connections must be enclosed and not exposed to water. It has to do with the risk of electrical shock to any of the divers that may be in the pool. (how ever low that risk might be)

Basically you would have to put them in a housing and run the shaft through a oil seal.... something along these lines.. http://www.homebuiltrovs.com/thruster.html

-Steve

[scubersteve]

Steve is right. MATE rules state that motors must be waterproofed.
Bear in mind that there isn't much pressure at the depths you'll reach in a pool and I doubt the MATE officials will be willing/able to check the efficacy of your waterproofing.
So as long as it looks waterproof, you should be okay.
I am dealing with a similar issue as a mentor for a MATE competition team.