Outrunner Underwater??

Anything to do with Propulsion.
Ian MacKenzie
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Joined: Jan 3rd, 2014, 10:04 pm
Location: Vancouver B.C. Canada

Re: Outrunner Underwater??

Post by Ian MacKenzie »

Check out SV Seeker on YouTube. He has an ROV link in his playlist. One of the vids is how to make a vacumm chamber. Another is sealing a motor.
rehoward
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Joined: Dec 15th, 2015, 5:41 am
Location: Everett, WA

Re: Outrunner Underwater??

Post by rehoward »

Ian MacKenzie wrote:Check out SV Seeker on YouTube. He has an ROV link in his playlist. One of the vids is how to make a vacumm chamber. Another is sealing a motor.
Good hit, thanks! Just what I was looking for.

Randy
rehoward
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Re: Outrunner Underwater??

Post by rehoward »

olegodo wrote:Ran the motor for another 2 hours yesteday with no change. Still runs fine and no noticeable wear, friction or noise change.

The nylon will absorb moisture and swell for sure but I'm not sure how big the effect will be. So I have the motor sitting in water now to see if it there is any notable difference in friction after one day in water.

I do believe the Bluerobotics thrusters are encased in some sort of epoxy to protect the winding of the motor. I plan on doing the same, but I'm not sure exactly what epoxy to use yet.
olegado, what are you using to power your test motor? I plan experimenting with several motors, my current one runs on 11.1 volts but others can run at higher voltage. I presently have a 12 volt 30 amp switching power supply that I hope I can use to run it. Are you using a power supply or batteries for your tests?

Randy
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olegodo
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Location: Bergen, Norway

Re: Outrunner Underwater??

Post by olegodo »

Hi,

I am using one of these cheap 12v 30A psu's from china.
Works great. I have never gone further then about 24A or so in my tests. But without problems.
I found out yesterday that it is also adjustable within a range of 10 to 16.4v.
I have never had any problems with voltage drop during testing either.
Protection circuits also work good. I have shorted it a bunch of times without it taking damage. It just turns off and stays off until you cycle the power.

Image
rehoward
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Joined: Dec 15th, 2015, 5:41 am
Location: Everett, WA

Re: Outrunner Underwater??

Post by rehoward »

olegodo wrote:Hi,

I am using one of these cheap 12v 30A psu's from china.
Works great. I have never gone further then about 24A or so in my tests. But without problems.
I found out yesterday that it is also adjustable within a range of 10 to 16.4v.
I have never had any problems with voltage drop during testing either.
Protection circuits also work good. I have shorted it a bunch of times without it taking damage. It just turns off and stays off until you cycle the power.

Image
Very cool. I bought one of those myself but have not tried it yet. Good to know about the voltage adjustment as there was no tech info sent with it. I assume it is the pot to the left of the terminal strip? I may buy a second one and run it in parallel for additional amperage output. Could run two in series for 24 volts I suppose as well?

Randy
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olegodo
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Location: Bergen, Norway

Re: Outrunner Underwater??

Post by olegodo »

Yes, the small pot adjust the output voltage.
Not sure if connecting them together in parallell or series will work. Never tried or had the need to.
I can't really see you needing more than the 30A if you plan on only testing one motor at the time really. You will fry the motor or esc long before you max out the psu.
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olegodo
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Re: Outrunner Underwater??

Post by olegodo »

Update on the 3d printed bushings I am testing.
The motor has been submerged in water for 6 days now. Although the motor hasn't been running the whole time, I have started it up from time to time and let it run for a while. Maybe it has around 10 hours in total run time now.
All data has been constant without any change from first test to when I tested it again last night. Really promising.
rehoward
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Re: Outrunner Underwater??

Post by rehoward »

olegodo wrote:I have some Igus composite bushings I want to test some day. I believe they are the same type as is used in the Bluerobotics thrusters.
Designed to work in submerged environments. Only problem was that the exact size I needed for my motors didn't exist so I have to file them down from 5 to 3mm if I want to use them. Both inner and outer diameter fits perfect.
If anyone wants to try them I would suggest looking at the Igus websites and sending them an email.
I got 5 of each size for free as a test :) I was quoted a price of $5 pr piece if I were to buy more.
olegodo, how did the Igus bearings hold up?

Randy
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olegodo
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Re: Outrunner Underwater??

Post by olegodo »

I haven't tried them yet. But I will eventually.
Pretty sure they will hold up as they are specifically made for this environment.
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olegodo
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Re: Outrunner Underwater??

Post by olegodo »

Last update on the printed bushings.

Done testing for now. Perhaps 15h total run time in water with no sign of wear or degradation.
I believe they will hold up well in water.
Now I also tested them bone dry 100% throttle and they lasted maybe 30-40 seconds before one of them melted.
This bushing was quite tight on the shaft so I guess the excessive friction caused a rapid heat buildup.
I will do another test with a pair that is slightly loose fitting and see how that goes.
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