Hactar wrote:

I was told this might be a good place to ask.

I'm looking for a slipring or commutator to go around the axle to my
wheelchair wheels. The catches are, it needs a 1" center hole (to go
around the axle nut), nothing can break if the wheel's removed (that's
easy, just push a button) and the body's put in a car trunk, and it only
has about 10mm clearance axially. On the plus side, it only needs to
carry a hundred mA, its radial clearance is something close to two feet,
and my maximum speed is around 75 RPM. Four conductors would be nice,
but I can live with two. Does such a thing exist for a reasonable amount
of money, perhaps in the model-making or robotics communities?

I have an idea about making one (per side) out of a CD-R, some
alternator brushes, and some sheet metal, if a pre-made one can't be
found. I figure I'll put the CD part on the wheel, to keep its angular
momentum down.

I'm afraid you won't find much for off the shelf slip ring assemblies,
and what there are will be $$$$. Give the small amount of power you need
to transmit, I'd consider using a rotary transformer coupling to
transmit the power as AC instead of DC.