Re: Waterjet Propulsion? [Not just AIP anymore <g>]

[Dave Everett <deverett@idx.com.au>]

At 05:45 PM 06-04-98 EDT, you wrote:
>
>Something comes to mind regarding delivering power through a partition
(hull?)
>without a shaft. In principle, a magnet is rotated inside which drives a
>magnet outside by the interaction of the respective magnetic fields, thus
>transferring power through the partition without a shaft piercing it.  I
>wonder if this principle could be applied to a submersible, but a few
>questions arise.  Does the steel hull prevent the magnetic field interaction
>through the hull?    Can significant torque be transferred this way? 

Last year I setup an experimental hydrogen production system that used
magnetic
coupling to drive a carbon rod on a leadscrew. The leadscrew was inside a
steel
case with 4mm walls. We had 2 plastic pieces lathed and drilled to take
neodynium magnets, on piece for the inside, one for the outside. 

The box was filled with a water and sugar solution that was very thick. The
outside plastic/magnet piece was turned by a stepper motor.

The coupling never slipped and handled any speed we gave it, although
steppers don't go all that fast.

Both plastic/magnet pieces had small steel points at the centre to act as
bearings.

>Would
>the required magnets really screw up compass navigation?

Even the magnet in your motors can have an effect, the Earths magnetic
field is tiny.
>
Dave Everett