[PSUBS-MAILIST] Brushless Thruster

Tue Oct 4 04:03:43 EDT 2016

I am not sure Brian.
I am thinking that a balanced mechanical seal would be necessary if I went
with a mechanical seal. Even though the motor is compensated it would
have more pressure pushing the faces together at depth. 
Every ROV  & submarine thruster seems to have a different seal.
I might try & contact this submersible pump manufacturer & see what they use.
https://www.flowserve.com/sites/default/files/2016-07/fpd-1362-ea4.pdf
They have been in the business of manufacturing submersible pumps for 50
years.
Their headquarters are in Hamburg. Carsten, if you know them I am wanting advice
for a mechanical seal for a pressure compensated thruster with a 10mm shaft 
rotating at 1500 rpm when under load.
Thanks
Regards Alan

Sent from my iPad

> On 4/10/2016, at 2:38 pm, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> I thought the ceramic seals were the way to go on those motors.
>  
> Brian
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
> Subject: Re: [PSUBS-MAILIST] Brushless Thruster
> Date: Mon, 3 Oct 2016 22:44:10 +0000 (UTC)
> 
> Alan,
> You are right, the mechanical seal is the easiest way to go.  My Perry thrusters had simple spring loaded seals with a sealed cavity behind the mechanical seal.   You will be oil filled, so the seal will have the back up oil.
> Hank
> 
> 
> On Monday, October 3, 2016 1:27 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Hank,
> yes I like the idea of going straight to the penetrator with the clear tube attaching
> on to a barbed fitting. I want to put a 4psi overpressure in the system & are
> intending to do this with compressed air; so need to tee in an air line. I also
> need an oil filling point, however the air connection point could double for this.
> I like the clear tube as it is a visual indication of the oil level.
> I have 2 lip seals at the moment. Hugh wasn't too impressed with that idea
> & thought I should go with a mechanical seal. From what I have read, the shaft
> the lip seal runs on needs to be plunge ground to a certain finish, & a mechanical
> seal would eliminate that precision process.
> Also I look at what other large manufacturers have done & figure they have
> done the research on seals & have the experience.
> Cheers Alan
> 
> Sent from my iPad
> 
> On 4/10/2016, at 12:37 am, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,
> You can make up a pretty simple penetrator for the wires, or why not leave the wires the way they are in the clear tube and run the tube to a penetrator on the sub that is made from a barbed fitting.  The clear tube can be oil filled and act as your compensator.  I know you already though of this.  I think the DW's work like that.
> If you are oil filled, why the mechanical seal.  Just go with a higher pressure rated lip seal.
> Hank
> 
> 
> On Monday, October 3, 2016 3:40 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Hi Hank, thanks.
> yes am intending on getting that type of seal, but I will try & get some advice
> on an appropriate seal for the viscosity & type of oil I am using (Morlina S2 Bl 10).
> Must be a bit barmy because I was getting quite excited about the new 
> compensating oil I bought. 
> I haven't quite decided how I am going to terminate the wires coming out of the 
> motor. At present I have the wires running through a clear hose up to a manifold.
> I say manifold but it is a modified brass T plumbing fitting. The hose is hose clamped
> to one end & the wires are silicone sealed coming out the other end. On the T I have
> a plug that I can remove to fill the tube & thruster with oil. This is okay for experimental
> purposes but will need to add pressure to the system & a through hull fitting
> when I mount it on the sub.
> Alan
> 
> 
> Sent from my iPad
> 
> On 3/10/2016, at 9:28 pm, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,
> That is great! well done..  What type of mechanical seal will you use?  Are you planning a spring loaded pump seal?  
> Hank 
> 
> 
> On Monday, October 3, 2016 2:07 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Just did a pool test of my latest brushless thruster.
> This thruster uses a 60kv (revs per Volt) 6374 (dimensions in mm) brushless
> sensored outrunner motor. The propeller was a 3 bladed 7&1/4" x 4" with no kort nozzle.
> I was getting 30kg (66lb) thrust from 30 amps off 52 volts (1560W) with the thruster
> oil filled. This seems comparable to what Cliff was getting from his Minnkota 101.
> The difference is this is a much smaller unit. I have been keeping a file on
> performance statistics of commercial thrusters & trolling motors & this is slightly 
> above average.
> The manufacturer told me not to run the motor more than 40 amps continuosly,
> so I am being conservative with the 30 amp draw. I could bump it up by putting
> on a bigger prop.
> Next step is to use it as a boat motor & notch up 100 or so hours, then build
> another housing with a mechanical seal.
> Added a couple of photos to the project page, but they loaded upside down for
> some reason. Couldn't change them. 
> http://www.psubs.org/projects/1235435392/brushlessthruster/
> Alan
> 
> Sent from my iPad
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