[Al Skierkiewicz]

If your design is not going to be greater than 360 degrees of rotation, you should be able to get along with just wire going down the center of your pivot. Slips rings add weight and size to the module and provide one more place where series resistance creeps up on your efficiency.
From R40 2011

The branch circuit may include intermediate elements such as COTS connectors, splices, COTS flexible/rolling/sliding contacts, and COTS slip rings, as long as the entire electrical pathway is via appropriately gauged conductors.

Emphasis mine, you may need to prove the slip rings you use are capable of the stall current in the motor you use to satisfy that last part. Assuming the rules remain the same.