[PSUBS-MAILIST] Brushless thruster test

[gbrown091 via Personal_Submersibles]

Thanks Alan appreciate your input on the thruster testing. 
Regards
Glen


Sent from Samsung Mobile

-------- Original message --------
From: T Novak via Personal_Submersibles <personal_submersibles at psubs.org> 
Date:30/01/2016  18:20  (GMT+02:00) 
To: 'Personal Submersibles General Discussion' <personal_submersibles at psubs.org> 
Subject: Re: [PSUBS-MAILIST] Brushless thruster test 

Thanks for the update, Alan.
It looks like your research is coming along quite well.
Tim
 
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan James via Personal_Submersibles
Sent: Saturday, January 30, 2016 1:47 AM
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: [PSUBS-MAILIST] Brushless thruster test
 
I had an initial pool test of my brushless thruster yesterday.
Thruster is on projects page http://www.psubs.org/projects/1235435392/brushlessthruster/
A bit of a mixed bag. Firstly I was testing it on 36-37 V & not 44 that it was designed for,
due to size restrictions on import of Lithium polymer batteries. I will buy the additional voltage.
   I was getting 5kg (11lb) thrust off 150W & 10kg (22lb) off 515W, which is comparable &
better than some commercial direct drive BLDC thrusters that I have specs on.
However I got to 13kg thrust & the propeller seemed to slip at that point & even though 
it was running at 2,200W I wasn't getting any more thrust. I was only a couple of feet out 
from the pool edge when testing, so that could be contributing.
Another factor could have been that the seal leaked badly & the motor was short circuiting 
through the water. Why did the seal leak? Possibly I damaged it hammering it in to it's housing
or because I didn't polish up the propeller shaft. 
I have other motors I will be testing, so a lot more work & learning to do on this one.
I did notice I had the same problem as  Cliff, with the motor wiring starting to wear through
where it comes out of the housing.
Cheers Alan
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