[PSUBS-MAILIST] Compensating oil

[T Novak via Personal_Submersibles]

Good plan, Alan. 

Getting tougher for me, the boys all have all the dive gear they need. What else is there?

Tim

 

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan James via Personal_Submersibles
Sent: December-12-15 1:57 PM
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Compensating oil

 

Thanks Hank, 

& Tim, I have a tradition of shopping on the 24th of Dec along

with all the other dysfunctional males.

Alan

 

  _____  

From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> >
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > 
Sent: Sunday, December 13, 2015 7:37 AM
Subject: Re: [PSUBS-MAILIST] Compensating oil

 

Tim,

 my x mas shopping is done, it is sitting in my shop :-)   

Hank

 

 

 

 

On Saturday, December 12, 2015 11:16 AM, T Novak via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

 

Hank, Alan

My personal favourite way to reverse the thrust is by rotating the motor-prop pod assembly 180 degrees.  Doesn't require a  sophisticated controller, but it does complicate the mechanical link.

Great link on submersible pumps, Alan.  

What are you guys doing on psubs, shouldn't you be out Christmas shopping?

Tim

 

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of hank pronk via Personal_Submersibles
Sent: December-12-15 7:51 AM
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> >
Subject: Re: [PSUBS-MAILIST] Compensating oil

 

Alan,

No clue on brand, there is substantial  thrust protection because the motor sits vertical and the weight of the armature is always on the thrust mechanism.   If I recall, they have bushings not bearings.  If you can add reverse and speed control, you have a winner.  I just have no expertise in that area.

Hank

 

 

On Saturday, December 12, 2015 8:22 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

 

It should be relatively easy to add reverse, but 

I presume they are either on or off, so you would need the addition of

a speed controller anyway. It would be interesting to pull one apart.

There might not be much in the way of a thrust bearing, as the pump impeller 

wouldn't have an axial load on the shaft like a propeller.

What brand was it again?

Alan

 



Sent from my iPad


On 13/12/2015, at 2:35 am, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

Alan,

I am still in favour of pump motors except I do not know how to reverse them.  As far as I can tell they are not reversible.  The efficiency in oil comes from the extremely smooth interior of the motor.  If you could reverse them, they would be perfect, they are cheap at about 200 dollars for a small 120v and they would be pretty easily modified to take a prop.  Oh ya, and they already have  thrust bearings.   The oil inside was real stinky, kinda like antifreeze.

Hank

 

 

On Saturday, December 12, 2015 3:24 AM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

 

Hank, 

what ever happened to your idea of using a submersible pump as a thruster?

Have just been doing a bit of reading on oil compensation of submersible pumps.

In this article....

http://www.pumped101.com/oilvsair.pdf

it states that with oil compensation there is only a loss of about 1&1/2% efficiency 

over an air compensated motor.....

 "What does reduce an oil filled motor’s efficiency is the energy loss due to oil circulation within the stator housing. 

As a rule of thumb, this circulation requirement reduces efficiency by about 1.5% when compared to an air filled motor. "

   Of interest was that they base this on the use of an oil "Shellflex 210" which has a viscosity of 20.3 cst at 40C.

I was recently trying to track down a silicone oil of 3cst thinking that I would need a really low viscosity to get reasonable efficiency.

A chemist I spoke to said at that low a viscosity it would be flammable.

Alan

 

 


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