Re: [PSUBS-MAILIST] linear actuators

[MerlinSub@t-online.de]

Hi Frank, some of my pumps for heatwater, small cooling water circulation etc are brushless. 

The run with 11 to 26 Volts. All my secundary systems runs on 24 Volts. 
If I charge the system onshore with a charger and reach over 26 volts,
say 26,1 Volts all brushless pumps stopped working.. 

The other brushes motor pumps are still working - just faster.. 

vbr carsten 
               "Electronic and submarines are like dog and cats.."


<ShellyDalg@aol.com> schrieb:
> Hi Alan. Sorry, I don't have any info on the Lenco's. Brushless is  
> definitely the way to go for any sub use. Better efficiency, less maintenance,  but 
> pricey.
> On the bellows thing.....by minimizing the air volume in the bellows at sea 
>  level, `the contracting air won't be a problem.
> Here's what I have done with the crappy Firgelli actuator on the  
> bench.------
> Retracted the rod completely, slipped the rubber bellows over the end and  
> attached it with duct tape and a hose clamp onto the body of the actuator. I 
>  spread some vaseline on the rod.
> I squeezed/retracted the bellows until it was completely collapsed with a  
> minimum amount of air inside.
> I then stretched the bellows "small end" onto the rod and hose clamped  it 
> on making sure no lubricant was near that end.  It's a tight fit on the  
> polished rod end.
> I removed the end cap on the actuator where the wires come out, slathered  
> it with auto gasket silicone and screwed it back on. There's some empty  
> space inside the actuator body but not a lot.
> After letting it set up over night, I hooked the two wires to a 9  volt 
> battery and extended the rod. 
> The rubber bellows expanded as expected. What happened was the bellows  
> "pleats" deformed and got all "wrinkly" because the outer circumference of the  
> pleats was being forced into a smaller diameter but the pleats themselves 
> stayed  more-or-less touching due to lack of air. The pleats kind of "sucked 
> down" onto  the shaft as it extended. This was part of the demonstration I 
> had planned for  the convention.
> I was having fun making it go in and out and so was observing how the  
> rubber was being stressed and stretched. After the fifth cycle the gasket stuff  
> on the end cap let go around the wires hole and air got sucked in there. I 
> could  tell easily because the shape of the bellows changed and after it was 
> fully  extended the rubber kept expanding back to it's original shape. Then 
> when I  retracted it again it swelled up like a balloon and finally forced 
> the air  past the duct tape/clamp on the body. 
> Now this was just a funky exercise on the bench and didn't last very long  
> but the point was to see what would happen to the bellows. 
> There is a bit of abuse to the bellows because they're not really designed  
> to stretch that way, but with a replacement cost of $6 each and pretty easy 
> to  slip a new one on there, if I can get  50 or a hundred cycles out of 
> the  bellows it's a good start.
> By looking at how the rubber deforms, it seems to me that a bellows with a  
> different profile would work without breaking down. The bellows I'm using 
> are  just mud boots for power steering linkage on a car.
> If I could get a "spiral" shaped bellows or maybe a "square" bodied one,  
> that might work better.
> Anyway, the concept seems to be workable but the materials need a little  
> tinkering with.
> Frank D.
>  
> 




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