Schick:
    I have had some experience with control and power wiring going into and out of rotating machinery; the machine was a strander, a machine which took individual copper strands (usually 19) and wound/stranded them onto one large reel.  The data and power transfer was accomplished with slip rings and brushes - and this was the greatest source of problems with this machine.  The power transfer was not so bad (it did not require extremely low resistance) but the data was a constant problem.  Only periodic cleaning and replacement of bad brushes kept it running at all.
    At the last Wire Show I attended before changing industries, the latest innovation in control of rotating machinery was on display - wireless data transfer.  Power was transfered with slip rings, and E-Stop control wires, but everything else was wireless.  I have noticed in my current industry that wireless data transfer is rapidly becomming more dependable, faster and cheaper; I'm thinking of wireless Ethernet in particular.  A stationary PLC communicating via wireless Ethernet with a remote I/O rack ought to do the trick.
    The wireless machinery I saw was manufactured by Bekeart (based in Belgium, but with plants in the US), and if you are not in a competing (wire manufacture) industry, they might share some insights with you.
    That's all I've got.  Best of luck.

How much power do you need and what kind of signal do you
want to access on the rotation part ?

<nbucska@pcperipherals.com>