[PSUBS-MAILIST] Air compensating thrusters

[via Personal_Submersibles]

The voice of experience. I knew about the brush problems, having fought those carbonizing issues with Hymak oil compensated thrusters (Pisces and Aquarius). Perhaps someone will develop this further and generate a white paper for the psubs archives? Air compensation certainly works for Karl S. and could well be a viable and inexpensive alternative for those in the planning/building stages.
Vance



-----Original Message-----
From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: psubs.org <personal_submersibles at psubs.org>
Sent: Fri, Jul 25, 2014 6:35 pm
Subject: [PSUBS-MAILIST] Air compensating thrusters





Hi psubbers,
in an attempt to get more information on the compensating issue
I contacted fugu subs, who I remembered used air compensation.
http://www.fugusub.com/

They operate small semi dry ambients probably to a max of 100ft. 
One thiught is that they operate in the warm waters of Florida where you would think
oil compensation would be an advantage in cooling the motors.
This is their reply.....
Hello Alan,

I seldom respond to technical letters, but I thought it best to save you some headaches.  Over the last thirty years, we have tried several types of oils for filling motors with, as some "authorities" had recommended.  Here's what happens:  On motors with brushes, the centrifugal force and pressure of the oil passing between brushes and rotors causes the brush to "lift off" of the rotor, causing power loss.  The motor slows down dramatically from internal fluid frictions as well.  Another issue is that some of these oils can wreck the vinyl insulate on wires and possibly o-rings.  On brush motors, 
oil is a failed prospect.  Stick with an air system.  Good luck with your project!


Kind regards,

Russell J. Canfield







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