[PSUBS-MAILIST] Pressure proof motor

[Alan James via Personal_Submersibles]

James,I like our air & oil compensating methods. I would think a seal capable of sealing to the depth we want would be expensive & require preparatory work on the propellor shaft to get it to the required smoothness. Also there would be more of a power loss compared with air compensation.The thruster I built used a 6374 out-runner hobby motor that a manufacturer kindly modified with a longer  propellor shaft made of 316, a finer motor winding to give it more torque, a hall sensor board was added & I had them put the wires out the back of the motor, rather than the top. I then built the housing & used a ceramic mechanical seal.  I was oil compensating it but using 5psi of air pressure to keep the oil in the housing. ( Centrifugal force was throwing the oil out & up the compensator / wiring hose). The out-runner motor has more torque & less speed than an in-runner motor, but the outside spins around & so there has to be a gap between the motor & housing. This means it cant be cooled directly through the motor housing & hence the use of oil. I like brushless motors rather than brushed. More efficient & better for oil compensating, as the oil tends to deteriorate the brushes & can lift them. Also, if anything goes wrong with a brushless motor it is most likely going to be the motor controller, which will be more accessible. I like the motor housings with the bolts running the length of the motor, clamping everything together, but I didnt have the skill or ability to make mine like that. So have had my eye open for a large inn runner brushless boat motor that I can easily air compensate. The other awkward part was adapting the stainless shaft to the propeller. So anyway, I prefer a ready made solution.I am also going for at least 100lb thrust with the theory that you dont have to use the power, but its there if you get into trouble in current.Alan 




Sent from Yahoo Mail on Android 
 
  On Fri, 24 Nov 2023 at 12:57 am, James Frankland via Personal_Submersibles<personal_submersibles at psubs.org> wrote:   Im just thinking out loud here all, so this could be a stupid idea.
Has anyone made or modified a normal trolling motor to be inside a pressure can?
I was just thinking about the possibility of doing so?  Put a normal Minn Kota or similar inside a can with some sort of heat transfer layer in between the motor casing and the inside of the can.  Then pass the shaft through a high pressure shaft seal?  Something like this.
https://ahpseals.com/product/vs-rs19a-2/

Would eliminate a lot of the pressure compensating issues, but then i suppose have its own complexities.
Any thoughts?
Regards
James
_______________________________________________
Personal_Submersibles mailing list
Personal_Submersibles at psubs.org
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20231123/d7028b24/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Screenshot_20210208_174925.jpg
Type: image/jpeg
Size: 383172 bytes
Desc: not available
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20231123/d7028b24/attachment-0001.jpg>