<div style="color:black;font: 12pt Arial, Helvetica, sans-serif;">The rim drives on Pisces 6 have NO seals, and no air spaces!!! And they are a lot less expensive than the ones from England. Which ain't the same thing as cheap.
<div>Vance<br>
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<div style="font-family:helvetica,arial;font-size:10pt;color:black">-----Original Message-----<br>
From: Alan via Personal_Submersibles <personal_submersibles@psubs.org><br>
To: Personal Submersibles General Discussion <personal_submersibles@psubs.org><br>
Sent: Tue, Jul 7, 2020 5:33 am<br>
Subject: Re: [PSUBS-MAILIST] Rim Drive Motors<br>
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<div>James,</div>
<div>I have looked briefly at them & think they look more problematic than</div>
<div>a conventional thruster.</div>
<div>There is a large rotor with the permanent magnets on the outside & the </div>
<div>fins on the inside. This runs inside a ring of coils. You would have to either</div>
<div>use large rotary seals to stop the water getting between the stator & rotor, or just</div>
<div>Coat the stator & rotor with a water resistant resin. The latter would be subject</div>
<div>to abrasion, particularly in seawater. Apart from that you have to transfer the</div>
<div>Lateral thrust from the propellors to the housing, & that would need either one</div>
<div>really large bearing, or a series of smaller bearings on both end housings ( for</div>
<div>forward & reverse). These bearings would have to be waterproof or sealed.</div>
<div>The main shortcoming I see with the standard trolling motor we use is that </div>
<div>they don't have a mechanical shaft seal.</div>
<div>I made a thruster with a mechanical seal, but it was a lot of work & I aren't </div>
<div>completely happy with the way I joined up the 3 housing sections. I was pinning</div>
<div>the sections together with screws rather than using long bolts that pull the</div>
<div>sections together as in bought thrusters that have a cast housing.</div>
<div>What I think would be ideal would be to find an off the shelf thruster & rebuild</div>
<div>the end section to add in a mechanical seal. </div>
<div>I am happy using the relieving pressure regulator that Cliff is using as an oil compensator.</div>
<div>Alan</div>
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<div><br clear="none">On 7/07/2020, at 8:14 PM, James Frankland via Personal_Submersibles <<a rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org" target="_blank" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div>
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<div dir="ltr">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.
<div>I got a quote once from a UK company to make one and it came in at £30,000. :/</div>
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<div><a rel="nofollow" shape="rect" target="_blank" href="http://krakenpower.de/?page_id=568">http://krakenpower.de/?page_id=568</a> </div>
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<div><a rel="nofollow" shape="rect" target="_blank" href="https://www.copenhagensubsea.com/vs">https://www.copenhagensubsea.com/vs</a></div>
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