[PSUBS-MAILIST] Brushless Thruster

Mon Oct 3 21:23:01 EDT 2016

It's not that they don't work underwater, it's just that if spinning up or down takes too long it's sub-optimal from a piloting perspective.

> On Oct 3, 2016, at 9:07 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Thanks Alec,
> didn't know that product existed. I found this video on an skf sleeve
> that is a good demonstration of how they are fitted.
> Be good to hear from Emile about his Protruar thruster. I don't know why 
> it wasn't working well under the water, as he doesn't go that deep on
> his tourist dives.
> Alan
> 
> 
> Sent from my iPad
> 
>> On 4/10/2016, at 12:56 pm, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Hi Alan,
>> 
>> Parker sells some little metal sleeves that stretch onto the shaft and are ground to the ideal finish for lip seals. It's a really easy way to meet the surface finish requirement, and they're super cheap too. 
>> 
>> 
>> Best,
>> 
>> Alec
>> 
>>> On Mon, Oct 3, 2016 at 3:26 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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>>>>> 
>>>>> 
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