Rotating Tree Power

[Tom Blevins]

I am looking for ideas on how to Rotate A Christmas Tree with a center pole with power. Unfortunately my design was not forward thinking enough to have a stationary center pole, so I need to rotate the entire tree but how do you do that with a power cord going up the center?

-Tom

[Travis Megee]

Slip ring.

On Thu, Dec 1, 2016 at 7:27 PM Tom Blevins <topazc...@gmail.com> wrote:

I am looking for ideas on how to Rotate A Christmas Tree with a center pole with power. Unfortunately my design was not forward thinking enough to have a stationary center pole, so I need to rotate the entire tree but how do you do that with a power cord going up the center?

-Tom

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[Andrew Ricke]

Adafruit is a good source for them for DIY as they are pricey otherwise.

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[Keith Rogers]

Is the power going to a stationary top ornament or does it need to distribute to the moving parts?

Sent from my mobile device

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[EschewObfuscation]

If you want to do it nerd style, you could use a supercap (or 10) and make brushes like an old style DC motor... charge up the cap each time it comes around? :)

[Jim S]

Even more geek points for a rotary transformer!

[EschewObfuscation]

Um... yes, you win! :)

[Tom Blevins]

Distributing power along the way. Not a solo topper. I have an extension cord with inline outlets to provide the distribution.

I thought there was a extension cord looping trick that would allow the rotation to occur and then slip before twisting.

-Tom

[EschewObfuscation]

On Thursday, December 1, 2016 at 7:27:27 PM UTC-6, Tom Blevins wrote:

I am looking for ideas on how to Rotate A Christmas Tree with a center pole with power. Unfortunately my design was not forward thinking enough to have a stationary center pole, so I need to rotate the entire tree but how do you do that with a power cord going up the center?

Okay, so I've been thinking about your question, and the pragmatic solution is indeed a slip ring. Store-bought units are pricey, but there are reasons to buy a manufactured one. If your application requires: high rotational speed, long service life, resistance to vibration, heat, corrosive atmospheres, safety while operated in a flammable/explosive atmosphere, if it must protect a delicate analog signal from external noise inputs, be light weight or low profile, handle dozens of circuits, rotate both directions, etc. Also, you can buy slip rings designed to surround a shaft... but you won't like the price or the delivery lead times.

None of these constraints apply to your project, so, happy day, we have a free hand: low speed, short service life sufficient, moderate voltage, low current, one direction of rotation. So let's just build one. Here's a possible approach:

If your central column is wood, I'd consider that sufficiently insulative, but if metal, you will want to insulate it. Now we need the rings themselves. One possibility is to wrap strips of copper around the pole, but another is to simply wrap several turns of solid copper wire, maybe on top of a thin film of epoxy? Copper's a soft metal, but it doesn't have to survive millions of rotations, so should be sufficient. Wrap the lower ring first, so the upper ring will simply have a bump in it due to the lower ring's wire; we'll expect the upper wiper to accommodate that bump as the shaft rotates.

For the wipers, I'd suggest almost any flexible metal would do; flexible is simpler than hinged. Maybe nothing fancier than strips cut from a food can? Some spring pressure should maintain contact with the rings. A common spring is a simple clothes pin.

So... I'd suggest the outer housing could be printed. Two copies required, one for each lead. C halves bolted together would be my preference; done right, adding washers would let it be used with a variety of shaft diameters, but a circular design slid on over the end of the shaft could work too. A pocket in the printed housing, shaped to hold a compressed clothes pin, could provide the contact pressure required. If you need to keep small fingers out of the works, then outer sleeves of pvc pipe could handle that.

What do you think?