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Before you get too carried away with it, you might
want to check the amount of eddy current losses you get. Moving magnetic fields
induce a current in metal (anything conductive), creating a 'drag' force on the
moving magnet. It's proportional to velocity, as well as magnetic field, so the
higher the RPM, the more drag you are going to have. If the RPMs are low,
like really low, then great. Unfortunately to get any 'power' through the
coupling at low RPM, you would have to couple a proportionally higher torque,
meaning bigger magnetic fields >> larger expensive magnets, and then more
drag again... Unless you use a non-conductive coupling wall, I see lots of
losses in your future :)
Motor manufacturers use special metal compositions
to minimize eddy currents, and those metals are structually lousy.
Plastic or glass walls would do the job, but of
course are going to have to be thick to handle any pressure. Magnetic force
diminishes very rapidly with distance (wall thickness). Think about the tiny
distances used in a motor between the magnets and the windings... if you want to
achieve the same torque with a significantly larger gap, then you would need
massively stronger magnetic fields, or massively greater diameter at the
coupling. Unless you can do this, you will need to multiply the RPM at the
coupler to acheive the same power.
Has this sort of coupler actually been used by
anyone? I hate to be a sourpuss, but it seems doomed to me. I'd love
to be proved wrong!
Mark
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