Hi Tom, thanks for the message.  The part you refer to is technically called a slip ring.  We use small models of these in our setup for the Ferris Wheel, and we're also using these for testing a kit for the Carousel.  We're hoping to have the Ferris Wheel kit ready in the next quarter, with the Carousel kit later in 2017.

Because we had to have a part custom-made for these kits, we don't have them in large quantity, and they are the most expensive part of the kit. If you're comfortable making your own electrical connections, there are some larger slip rings commercially available from suppliers like Adafruit (https://www.adafruit.com/?q=slip%20ring&) that you might be able to make fit into LEGO geometry. We had to look long and hard to find a ring small enough to fit inside a Technic brick, and these are the ones we special-ordered for our kits. We may be offering these for sale later in 2017 (if we're able to get a larger order placed with the manufacturer), but for now we're saving them for the Ferris Wheel and Carousel lighting kits. If you'd like to be added to the notification list for either kit, please send us a note through the Contact form on our website.

Thanks again for your post!

This slip ring would be useful for the Wind Turbine (Set 4999) too!  I've wanted to have a blinking red light on the tip of each of the blades.

Jim Pirzyk That would look amazing!  Looking at the setup of the kit, it looks like the entire weight of the blade assembly rests on the axle that attaches to the main assembly.  The trick with using the slip rings is that you need to find a way to remove the stress on the rotating part of the ring itself.  This is easy to do in the Ferris Wheel because there are two support points for the main wheel, so if the slip ring is inside one end, the main LEGO parts will continue to support the weight of the wheel from the other side.  With the Carousel, there are multiple wheels that rotate around the upper outside of the Carousel, relieving downward pressure on the slip ring.

In the Turbine, what are your thoughts about how this could be implemented?  Jim, I know you're the MASTER of drilling holes through tiny spaces-- if there was a way to drill through the center of the support axle (without weakening it), perhaps wires could be run through and the slip ring itself could sit behind the terminating gear in the top motor assembly-- this way, the LEGO elements would support the weight of the blade assembly while the slip ring could be mounted at the rear inside the main motor assembly without any downward or shear pressure.  We don't have that kit, though, so can't really speak to how it might work.

Maybe I can bring a ring to Chicago next week for the Cantigny show, and we can experiment?

Hrm...

I'll have to think about that.  My first though is to go with a non LEGO solution, like swapping out the axle brick with a brass one.

Jim Pirzyk That could work too!