[PSUBS-MAILIST] Brushless thruster test

[Alan James via Personal_Submersibles]

Seal leak problem solved.I had put in a 12mm seal instead of a 10mm ID seal.Dumb, didn't even realize I had some that size.Alan
 

      From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Sunday, January 31, 2016 7:43 AM
 Subject: Re: [PSUBS-MAILIST] Brushless thruster test
   
Hank, Tim.With a load on it should be about 1300 rpm.It was leaking just sitting in the pool. When I got homeI poured a low viscosity oil in the wire entry & it just flowedout the seal. It is quite a learning experience. There are some big gaps in my understanding of the maths of what is going on.I am getting a 1500W sensored motor with low kv & an operational voltage of 44Vmade up for me. The motors I have are sensorless & it is hard to find a goodspeed controller with reverse for sensorless motors.Alan
 

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Sunday, January 31, 2016 7:08 AM
 Subject: Re: [PSUBS-MAILIST] Brushless thruster test
  
Alan,That motor looks pretty nice!  I still think rpm is your enemy, seal wise.Hank 

    On Saturday, January 30, 2016 9:20 AM, T Novak via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
 

 #yiv0105260126 -- filtered {font-family:Helvetica;panose-1:2 11 6 4 2 2 2 2 2 4;}#yiv0105260126 filtered {panose-1:2 4 5 3 5 4 6 3 2 4;}#yiv0105260126 filtered {font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;}#yiv0105260126 p.yiv0105260126MsoNormal, #yiv0105260126 li.yiv0105260126MsoNormal, #yiv0105260126 div.yiv0105260126MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:12.0pt;}#yiv0105260126 a:link, #yiv0105260126 span.yiv0105260126MsoHyperlink {color:blue;text-decoration:underline;}#yiv0105260126 a:visited, #yiv0105260126 span.yiv0105260126MsoHyperlinkFollowed {color:purple;text-decoration:underline;}#yiv0105260126 span.yiv0105260126EmailStyle17 {color:#1F497D;}#yiv0105260126 .yiv0105260126MsoChpDefault {font-size:10.0pt;}#yiv0105260126 filtered {margin:1.0in 1.0in 1.0in 1.0in;}#yiv0105260126 div.yiv0105260126WordSection1 {}#yiv0105260126 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 housingor 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 throughwhere it comes out of the housing.Cheers Alan
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