Wireless power transmission in a POV clock

[boylesg]

How would you go about transmitting power wireless from the stationary part of a POV clock to the spinning part?
Would you use an an SMPS arrangement and would these work without a core, i.e. just two loops of wire in close proximity?
If so does anyone no a good URL that explains the very basics of designing a SMPS.

 

[BradtheRad]

This thread has two pages of discussion about an air-core transformer in a spinning clock.

https://www.edaboard.com/threads/308031/

- - - Updated - - -

It has a link to this project on the internet:

http://www.oocities.org/tjacodesign/propclock/propclock.html

My suggestion is to install a cassette motor inside the spinning clock. Lock the shaft to a board. That is your axle. Now you have a generator.

 

[betwixt]

Just curious Brad - I can see how spinning the motor body with the shaft locked will turn it into a generator but how then do you make the 'prop' turn around?

I've been thinking of ways to make a POV clock using two axis scanning, one being the rotatating disk but instead of emitting light directly from it, to bounce a light (maybe laser) from a second source. Kind of like mechanical TV systems used to work. I've got a Sterling engine fan on top of my log stove I would love to turn into a clock but the speed varies according to temperature and I don't think the electronics would take too kindly to ~150C temperatures!

Brian.

 

[BradtheRad]

Just curious Brad - I can see how spinning the motor body with the shaft locked will turn it into a generator but how then do you make the 'prop' turn around?

I only thought as far as the concept, I guess. I picture the entire motor body is inside the rotating clock, along with the circuitry and propeller, all in one unit. However it's true there may be further concerns about making a propeller clock that I'm not aware of.

In fact as I think about it, the motor will wear out quickly because it is running at 5 or 10 rps full time. I don't suppose my generator idea is feasible.

 

[betwixt]

You would need to have the power source rotating with the motor body so I don't think conceptually it would work like that. An alternative might be to induce power into fixed coils around the circumference of the prop circle and place fixed magnets around it's locus. Not efficient but it would get over the power transfer problem.

I was thinking along the lines of maybe four, thin, prop blades with tiny mirrors fixed at distances 1-2-3-4 1-2-3-4 1-2-3-4 1-2-3-4 from the axis, maybe repeating more than once, then flashing fixed LEDs at each group as it rotates. It would be difficult to 'interlace' but a novel challenge!

Brian.

 

[BradtheRad]

Reading the aircore transformer thread (link in post #2), I gathered that the propeller clock is housed inside one pipe, rotating inside a larger pipe. The big hurdle is wireless transfer of electric power. Stationary coils spaced around the outer pipe. Moving coils inside the spinning narrow pipe. Feasible although inefficient.

I thought this could work instead. Just spin the entire project around the motor shaft:



Not shown is a stationary motor, turning the project via rim drive, belt drive, etc.

The rotating tube needs to be stabilized, unless the motor shaft is solidly locked.