[PSUBS-MAILIST] motor pod testing

[Alan via Personal_Submersibles]

Hi Rick,
I presume that was miracle oil!
I have tried a few oils in my experiments building thrusters.
I have gone to silicone as I believe Emile & maybe Carsten have.
With the various oils, in a short time some of the insulation on my wires degraded.
Also I'm suspicious that the glue positioning my hall sensor board went soft
in the oil & let the hall sensor move.
Greg also noticed some deterioration of plastic in his oil filled thruster.
I did experiments soaking various plastics in WD40 etc & were getting a
break down of some of the plastics in a short time.
You might get away with it depending on the use of or type of plastic in the
motor. Brian better cross his fingers as several gallons of silicone would be 
pretty expensive.
Alan


Sent from my iPad

> On 3/04/2018, at 5:32 PM, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Seems like quite an expansion rate for the oil you used. I will be using merical oil and am hoping for very little volume expansion so the bladder's don't have to be that large.
> Rick
> 
>> On Mon, Apr 2, 2018 at 6:29 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Hi Brian,
>> you should get a lot more cooling in the water. When testing my lights, they
>> heated to the point where you could only touch them for a few seconds
>> after 5 minutes but stayed warm for an hour in water.
>> You were testing with no load on the thruster. It will heat up quite a bit
>> quicker with a load on. 
>> Cheers Alan
>> 
>> Sent from my iPad
>> 
>>> On 3/04/2018, at 2:52 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> 
>>> Hi All ,         Tested my motor pods today for about an hour at about 3/4 maximum speed.   Had about 8 feet of 1/2" vinyl tubing coming from the top of the motors going straight up into the air and hanging from my overhead I beams.  Had the vinyl tubing connected to small inner tubes that had the air evacuated out of them.  It was a cool day ( overcast, 60 degrees) . I ran the motors for over an hour, by the end of the hour the wd40 had climbed the whole 8 feet of tubing to the base of the inner tube.  The motor pods were warm.  If the sub had been in the water I don't think I would have had as much expansion of the oil.  So I think that is going to work pretty good.   Gives me a chance to run the batteries down significantly to see how my battery charger works with drained batteries, and how long it takes to bring them back up.
>>>  
>>> Brian
>>>  
>>>  
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