[PSUBS-MAILIST] MK 2 Brushless Thruster

[Stephen Fordyce via Personal_Submersibles]

Hi Alan,
That looks great!  Very small for the power.  A couple of comments/queries:
- There's no second bearing or thrust bearing - perhaps these are not shown?
- Just wondering how the wiring tube is connected?  Ie. tapped hole for
a cable gland or compression fitting?
- How is the motor held in place within the housing?
- I'm guessing the motor has a carbon steel shaft and the external
propeller shaft should be SS316 - are you going to weld them together or
connect mechanically?

Cheers,
Steve

On Fri, Mar 25, 2016 at 8:13 AM, Alan James via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> OK Hank I will bolt the front section on.
> I had problems machining the bearing seat on the first thruster as the
> front section was one piece & I needed a long boring tool. I will have the
> same trouble if I have to machine these after welding. I will probably
> loc-tite everything in on the front section as it doesn't need to come
> apart.
> The whole thruster housing (2000W) is only 80mm x 174mm (3&1/4" X 7")
> & there is very little to it.
> Are you planning any other submarine events in Europe apart from visiting
> Emile?
> I went up to Cherbourg & had a look at the submarine museum. You could
> spend
> a day there, I am sure your wife would love it.
> Cheers Alan
>
>
> ------------------------------
> *From:* hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org>
> *To:* Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> *Sent:* Friday, March 25, 2016 9:05 AM
>
> *Subject:* Re: [PSUBS-MAILIST] MK 2 Brushless Thruster
>
> Alan,
> I like the two seals also and now that you mention you are putting in a
> fill plug to vent air-I am with you.  I would get it welded before you
> machine the bearing seats etc, if possible.
> I would still make both ends bolt together-there is nothing like having it
> come apart to work on it.  My Perry thrusters break down into a million
> pieces and it is real nice to work on.
> Hank
>
>
> On Thursday, March 24, 2016 1:55 PM, Alan James via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>
> Hank,
> I left out some details on that drawing. The back end fits the same
> as the front & has a radial o-ring seal on the end housing & 6 cap screws
> that
> bolt in to the central housing.
> Alan
>
>
>
> ------------------------------
> *From:* hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org>
> *To:* Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> *Sent:* Friday, March 25, 2016 1:31 AM
> *Subject:* Re: [PSUBS-MAILIST] MK 2 Brushless Thruster
>
> Hi Alan,
> It wouldn't hurt to clamp the end cap tight but you do have a nice
> shoulder for the end cap to sit on.  Any time I make a part that can and
> usually does warp, I make it oversize and machine it true after welding.  I
> am curious why you want to weld it-that big shoulder has room for an
> o-ring.   I would also ditch the second seal-it is an air trap.    Great
> project!
> Hank
>
>
> On Thursday, March 24, 2016 12:27 AM, Alan James via Personal_Submersibles
> <personal_submersibles at psubs.org> wrote:
>
>
> This is my latest brushless thruster design for scrutiny.
> The last thruster I made was 2 piece with one seal.
> I machined the last version out of aluminum rod, which was expensive &
> difficult.
> The end pieces in this design are from solid rod but the mid section is
> from a stock tube
> that I intend to have welded to the propeller end. The back end is bolted
> on.
> Am I likely to get distortion when welding the two sections together?
> There is a sleeve
> press fitting to help give it some rigidity for welding. Should I make a
> jig to clamp it in
> for welding?
> The thruster is for 500ft depth & is oil filled with a slight over
> pressure above ambient.
> Oil filled mainly for cooling purposes, but also as a secondary defense
> against any leaks,
> & for lubrication of bearings & seals. I am using low pressure lip seals &
> have a double
> seal redundant arrangement. The outboard seal is orientated to keep the
> oil in & with the
> internal overpressure should keep the water out. The outboard seal should
> fail first as it is
> exposed to abrasives, especially in sea water. The inboard seal is
> oriented so that it keeps
> any water out that may get past the outboard seal.
> The tube coming out of the seal cavity is for pressurizing it & for
> collecting any water that
> may get through & come out of suspension. I am thinking of putting a water
> sensor in there.
> Any comments welcome.
> Alan
> p.s. if image isn't big enough keep hitting ctrl & + TO ENLARGE.
>
> [image: motor cut away.jpg]
>
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
>
> _______________________________________________
> 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/20160325/8cde5054/attachment-0001.html>