answer to waterproofing an electric motor housing

[azureus]

Mechanical seal Eng. Recently built a bow thruster for my sailboat. I tried using a sealed bearing for a shaft seal however it leaked a small amount of water. I attached an airline to the motor casing and pressurised it using a small air compressor at about 10 psi. This seems to work, however next time I will use the shaft and bearing from a automobile waterpump .....Azureus

 

[MikeHalloran]

In recent years, bearing distributors have been selling, 'sealed' bearings with 'non- contact' or 'labyrinth' seals. Maybe you got one of those; distributors' counter help doesn't seem to discriminate those from 'contact seals', which actually seal. The part numbers are distinct, but there is an education issue that hasn't been adequately addressed.

That said, I would trust a 'contact' bearing seal to keep grease in the bearing, and I have trusted them to keep oil in gearboxes, but I don't think I'd trust them to keep water out of an electric motor. Maybe a sealed bearing with an auxiliary lip seal, but not the sealed bearing alone.



Mike Halloran
Pembroke Pines, FL, USA