|
Bill Beaty has created a neat way for magnets to be levitated. If you build it please be cautious since you could loose your hand if you aren’t careful. "While working on science museum exhibits in 1990 I came up with the above idea: it is known that a spinning metal disk will lift and fling a strong magnet. Therefore, metal rods with opposite spin will lift a magnet but WON’T fling it sideways. It works! I used "sched-80" heavy wall copper tubes about 1-3/8" diameter, 12" long, with 1/4" wall thickness. I hammered aluminum plugs into the tubes, carved shaft-tips with a lathe, built endblocks and bearings, spun them with an AC/DC motor, and managed to levitate a stack of two 3/4" diameter neodymium magnets. The spinning tubes must move at about 5000 RPM before the magnet starts floating. " |
August 18th, 2008
I have been doing this for years!
It did start as a way of avoiding breaking and I noticed the same results.
August 18th, 2008
I came up with a better idea, but it’s way complicated, so never built.
Use 1/2″ Al plate to make a 6″ disk, as well as a 12″ O.D. ring with 8″ I.D. center hole. Figure out how to mount these parts on two separate DC motors so they can be spun at high speed. (Use non-magnetic shaft material. Perhaps mount the 12″ ring on a short piece of 10″ plastic pipe with a plastic disk connected to a motor shaft.)
Then arrange the motorized disk and ring so the 6″ disk is positioned within the 8″ hole in the ring. Then spin them at high speed in opposite directions.
If a small 3/4″ cylinder supermagnet is placed in the 1″ slot between the disk and ring, it should levitate in three dimensions. There will be some inductive drag, but if you adjust the two motor speeds, it should cancel out. The magnet should just hang there unmoving. Once the first magnet is hovering, add a bunch more. Align their poles of course, and they will repel each other to form a magnet-array ring which hangs in the space between the whirling aluminum parts. Bump one magnet and a wave should pass through the rest. If the motors lose power and the magnets crash into the ring, they’ll come flying out like musket balls. Maybe it needs a close-fitting plastic case? But it’s not Mad Science if you don’t risk messy death during every moment of testing!
Does this really work? I dunno. It might be too unstable. Probably it will run at fairly low RPM, since we just need a ?30MPH? surface velocity. An axial restoring force does exist, but it might not be as strong as the magnet’s weight. If it’s too weak, then the whole assembly would have to be turned on its side like a wheel, rather than rotating flat like a turntable. That way a feeble axial force would entrain the magnets horizontally, while a strong repulsion force from the ring would lift them upwards/inwards.
August 19th, 2008
[...] hackedgadgets, amasci A+Featured Hacks, ac dc, bearings, Consumer, Cool, copper tubes, dc motor, demonstration, [...]
August 20th, 2008
[...] - All-mechanical magnetic levitation with neodymium supermagnets [via Hacked Gadgets] [...]
August 29th, 2008
Crazy work!
November 14th, 2008
[...] Bill Beaty documents his recipe for levitating neodymium magnets using two rotating coppers tubes. Note: The aptly named “Fantastically Dangerous Mechanical MagLev” could indeed seriously injure a person (you’ll notice Bill uses a clear plastic covering over the tubes to prevent the aforementioned nastiness) - While working on science museum exhibits in 1990 I came up with the above idea: it is known that a spinning metal disk will lift and fling a strong magnet. Therefore, metal rods with opposite spin will lift a magnet but WON’T fling it sideways. It works! I used “sched-80″ heavy wall copper tubes about 1-3/8″ diameter, 12″ long, with 1/4″ wall thickness. I hammered aluminum plugs into the tubes, carved shaft-tips with a lathe, built endblocks and bearings, spun them with an AC/DC motor, and managed to levitate a stack of two 3/4″ diameter neodymium magnets. The spinning tubes must move at about 5000 RPM before the magnet starts floating. - All-mechanical magnetic levitation with neodymium supermagnets [via Hacked Gadgets] [...]