Saturday, July 12, 2008

Boredom strikes!

And when it strikes, it strikes hard, at the very heart of science! BWAHAHAHAHA

Ok, not really. But I did finally figure something out for an eddy current heater thingamabobber I've had on my mind.

I took something from a previous boredom session, a wooden disk with a spindle, and I centered and drilled four holes in one of the hard drive platters. That, and a clamp for the magnet, and I had my demonstrator.

And, with the drill press on it's highest speed setting, gets too hot to touch. Myth confirmed. Wait, wrong show...

1 - I'm not sure what the drive platter is made of, and it may not be as conductive as an aluminum or copper disk.
2 - The magnets could be closer together, and since magnetic fields run on the inverse square of distance, that will increase the eddy and the heating.
3 - I'm limited here by speed, but a bigger disk would have higher rotational speed at the edge. With the original wind powered idea, I'll either need a big disk or a gearbox, with the latter being more likely.
4 - There are stronger magnets out there, and multipolar setups work much, much better than what I have.

Still, too much stronger and I'll either overstress the drill press, or actually heat the disk to a failure point... which I really kinda wanted to see... at least a dull red. I figure I got around 250-300 degrees F running, but it falls off fast because of surface area and heat conductivity when it's stopped.

The "end game" of this idea was a little wind-powered unit for arctic climes... basically, cheap free heat with no maintenance. If you make heat with friction, you eventually wear it out; make heat with electrical generation and resistance, and you drive the unit price up. Make heat with a cheap aluminum disk in an oil bath running between a series of rare earth magnets, and you've got something simple, inexpensive, and it'll run forever.

I mean, it's not like there's a shortage of wind above the arctic circle...