[PSUBS-MAILIST] Motor modification

Mon Dec 5 17:04:54 EST 2016

Alan,

I am confused (which doesn't take much) but you talk about doing a test to
collapse a PVC hose. I assume that the hose leads from an oil filled vessel
to a bladder both being completely filled with a dielectric fluid/oil. So I
was thinking that the hose and bladder were to allow for slight expansion
as the oil warms up from use so that the factory prop shaft 0 rings would
not be extruded outward from excess pressure?. This is based on there being
NO air in the vessel, hose or bladder. I didn't realize that there were two
0 rings on the Minn-Kota prop shaft so I do see what you are saying about
the outer most 0 ring pushing in with increased pressure. The way I
understand it though is if you have ANY air in the system than you are
defeating the purpose of having a hose and bladder, correct?

Rick

On Mon, Dec 5, 2016 at 11:03 AM, Alan James via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Some compensating thoughts.
> On James Cameron's sub they used IV drip bags. I am not sure what they
> were compensating.
> These come with various means of hose attachment.
>    With regard to the wrap around hose method; I did some calculations on
> a standard pvc hose, & surprisingly
> the colapse pressure was around 100psi. I am sure one of Nuytco's
> technicians told me they crimped the hose
> that was compensating their lights, to initiate the collapse of the hose
> for compensation.
>    The industry standard for thrusters seems to be around 4psi internal
> overpressure,
> but the compensators they use for this are relatively expensive. Hugh came
> up with
> the novel idea of using a releiving regulator set at 4psi (Parker PR364).
> Cliff is using this.
> This could be used for air or oil compensation.
>    The seals need oil for lubrication, & I have read that they can use
> about a teaspoon a day. Based
> on that I would have some sort of reservoir.
>    Depending on the motor it may be tricky to get all the air out. If you
> have a bearing in a bore
> followed by a seal, the air / oil would have to move through the bearing
> which may be a sealed type
> or packed with grease. The Minn kotta diagrams I have seen show 2 seals;
> so how do you get oil or
> ambient pressure between those? One will fail when you exceed it's
> pressure limit.
> Alan
>
>
> ------------------------------
> *From:* James Frankland via Personal_Submersibles <
> personal_submersibles at psubs.org>
> *To:* Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> *Sent:* Tuesday, December 6, 2016 4:44 AM
> *Subject:* Re: [PSUBS-MAILIST] Motor modification
>
> Hi Antoine\Hank.
>
> Thanks guys.  drinking bladder looks good.  I was thinking of a furniture
> lift bag, which is very similar.  I use a hot water bottle for the aft
> motor.
>
> Hank, what do you use for a bladder?
>
> Thanks
> James
>
> On 5 December 2016 at 13:18, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> James,
> I put my fill plug under the prop, in the flat end cap,  and it works like
> a dream.
> Hank
>
>
> On Monday, December 5, 2016 5:37 AM, Antoine Delafargue via
> Personal_Submersibles <personal_submersibles at psubs. org
> <personal_submersibles at psubs.org>> wrote:
>
>
> Hi frank
> I have done something like that for my prop shaft seal oil filled
> compartment.  But first i removed the hose and filled with a serynge with
> long steel needle. Then put the tube and filled it with the serynge.
> The tube is flexible and transparent, from endurance sport
> platypus drinking bladder
> Works well
> Regards
> Antoine
> On Monday, December 5, 2016, James Frankland via Personal_Submersibles <personal_submersibles at psubs.
> org <personal_submersibles at psubs.org>> wrote:
>
> Hi All
>
> I have been talking to Rick about motor compensation which has got me
> thinking.
>
> I originally did my motors like other psubbers have done with the rubber
> tubes around the sides, but have found them a real pain to fill.  Problem
> is the location of the tube, plus the tiny bit of protruding pipe nipple on
> the inside.
>
> So, I modified the motors by drilling a hole in the top part of the
> aluminium endcap and use that now as the vent\final fill.  Its better, but
> still awkward.
>
> I have suggested to Rick this idea, which I am tempted to adopt myself.
> Blocking off the existing side mounted pipe nipples and
> filling\venting\compensating all from the one top hole.  There would be a
> rubber bulb of some sort on the end of the pipe.  2x pictures show filling
> and operation.  Appologies for rubbish drawings, im at work.
>
> What does everyone think?
>
>
> 
> 
>
>
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