[PSUBS-MAILIST] Minn Kotta 101 - Thruster Reliability

[Cliff Redus via Personal_Submersibles]

 Alan, a couple of points. I am not arguing that an oil compensated 101 is better than a purpose build brushless thruster.  It is just a cost thing for me.  Unless you are a machinist, my guess it is going to cost you several thousand dollars in the states to machine the thruster you have designed. OTS thrusters go for $5K and up and run at a much higher voltage than psubbers normally run at.  Using the 101, with all its weaknesses, is a low-cost way for psubbers to fabricate a thruster.  Given these constraints, I am just trying to make these function more reliably.
With any luck, at the speed Hank works, he has already fabricated a 1-atm 101 with a magnetic coupling as tested to 1000 ft and all we have to do is work up the fabrication drawing!
Keep us in the loop on progress on your thruster project.
Cliff
    On Friday, July 28, 2023 at 09:46:14 PM CDT, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  
 
 Cliff,I don't think brushed motors are the way to go.The brushes can contaminate the oil & lift due to the centrifugal force of the oil. And they are less efficient than brushless motors. Also the 101s have that double o-ring seal system, that means one of the o-rings will fail when over 30ft or so.A descent brushless option with a ceramic mechanical seal and silicone compensation would be a big improvement.I bought some of the Shell Morlina some years ago.  An industrial chemist advised me it was low in aromatics and less likely to dissolve plastics than other options. I believe it was used to lubricate high speed spindles etc.It still had an effect on plastics.Alan 
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  On Sat, 29 Jul 2023 at 12:42 pm, Cliff Redus via Personal_Submersibles<personal_submersibles at psubs.org> wrote:   _______________________________________________
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