[PSUBS-MAILIST] Rim Drive Motors

[Alan via Personal_Submersibles]

James,
I have looked briefly at them & think they look more problematic than
a conventional thruster.
There is a large rotor with the permanent magnets on the outside & the 
fins on the inside. This runs inside a ring of coils. You would have to either
use large rotary seals to stop the water getting between the stator & rotor, or just
Coat the stator & rotor with a water resistant resin. The latter would be subject
to abrasion, particularly in seawater. Apart from that you have to transfer the
Lateral thrust from the propellors to the housing, & that would need either one
really large bearing, or a series of smaller bearings on both end housings ( for
forward & reverse). These bearings would have to be waterproof or sealed.
The main shortcoming I see with the standard trolling motor we use is that 
they don't  have a mechanical shaft seal.
I made a thruster with a mechanical seal, but it was a lot of work & I aren't 
completely happy with the way I joined up the 3 housing sections. I was pinning
the sections together with screws rather than using long bolts that pull the
sections together as in bought thrusters that have a cast housing.
What I think would be ideal would be to find an off the shelf thruster & rebuild
the end section to add in a mechanical seal. 
I am happy using the relieving pressure regulator that Cliff is using as an oil compensator.
Alan



> On 7/07/2020, at 8:14 PM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Maybe we could have some sort of community team think and figure out how to build some of these rim drive motors.  Emile has them on Drebbel and they seem to be the answer to all the problems.  
> I got a quote once from a UK company to make one and it came in at £30,000.    :/
> 
> http://krakenpower.de/?page_id=568 
> 
> https://www.copenhagensubsea.com/vs
> 
>  
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