[PSUBS-MAILIST] Thruster Reliability

Wed Jul 26 08:50:38 EDT 2023

 Hank, when you do your yearly maintenance on these motors, do you also replace the lip seals and shaft bushing, and do you inspect brushes for wear, or do you just drain and refill without tearing them down?
Cliff
    On Tuesday, July 25, 2023 at 07:55:11 PM CDT, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

  Alec, I am working on a magnetic coupler end cap this winter.  I have had very good luck with WD-40 and have two 55 lb motors still running after more than 20 years.  The only difference is, I use much smaller motors.  My oil goes black right away and I do get a very small amount of water by season end.  I drain the dirty oil and replace.  
The first thing to do is to strip down a motor and plug the shaft hole and do a pressure test on the housing.  No point in working on a seal or magnetic coupler if the housing fails early.Hank
    On Tuesday, July 25, 2023, 06:19:24 PM MDT, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Here's my inspiration. I've seen several original Kittredge subs still kicking with their original 1-atm, ceramic seal thrusters that are probably 40 years old. Their use is occasional, for sure, but they're maintenance has probably been zero. What I'd like to explore is doing what the Captain did, except with a Minnkota. If the bushings and brushes are dry and in 1 atmosphere, with the normal lubrication (a little grease on the bushings,) then I don't see why they can't have the same life as when they go fishing. 

On Tue, Jul 25, 2023 at 7:53 PM Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Thanks for the credit Alec, I think it was Brian Hughes ideafrom a previous discussion. Glad we are making some progress.As far as the oil / air debate is concerned, I believe Carsten said that you only need a few drops of sea water into an air compensated thruster to wreck it, whereas if there is oil in there the water doesn't do the same damage.Your compensator can be used as an air over oil system.You could even run 2 thrusters off the same compensator as a test. One with oil, one just air.Alan
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  On Wed, 26 Jul 2023 at 11:19 am, Alec Smyth via Personal_Submersibles<personal_submersibles at psubs.org> wrote:   _______________________________________________
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