[PSUBS-MAILIST] Compensating oil

Tue Dec 15 17:34:36 EST 2015

Hi James,Hugh's Com sub has hydraulic thrusters & he mentioned replacing them.They are not as efficient as our electric thrusters &  would be quite noisy with the hydraulic pump in the hull.Cheers Alan
      From: James Frankland via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Wednesday, December 16, 2015 5:13 AM
 Subject: Re: [PSUBS-MAILIST] Compensating oil

I met up with the guy who owns\operates the Mortze submersible  Russian made.  He told me that it runs completely on hydraulic motors and he has hardly had to service anything for 20 years...  I could ask him about them if anyone likes?REgardsJames
On 13 December 2015 at 01:38, T Novak via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

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 alongwith all the other dysfunctional males.Alan From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <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> wrote: Hank, AlanMy 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>
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> wrote: It should be relatively easy to add reverse, but I presume they are either on or off, so you would need the addition ofa 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 

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On 13/12/2015, at 2:35 am, hank pronk via Personal_Submersibles <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> 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.pdfit 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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