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Discussion board help and admin topics => Half Baked Ideas => Topic started by: Azorus on November 20, 2009, 02:27:19 AM

Title: Magnetic Gear
Post by: Azorus on November 20, 2009, 02:27:19 AM
I am still kinda new here but I recently have been playing with my old magnets and though why not use them as gears.  I you put north on one spindle of a disk and north on another and have them spaced correctly wouldn't energy transfer be uniform?
Title: Re: Magnetic Gear
Post by: mr_bojangles on November 20, 2009, 11:44:59 AM
gears tend to transfer energy with the least amount of friction possible

i am not positive as to what exactly you mean by putting north on a spindle, but i am not aware of a method to transfer energy between two magnets that behaves in a way similar to gears

im guessing you mean use opposing fields to transfer angular distance

the problem would be when you tried to put a load on the second magnet

you might be able to rotate it, but if you put resistance on it, it most likely wouldn't hold up


its an interesting idea and maybe you just need to play around with it and see what you can get to happen
Title: Re: Magnetic Gear
Post by: DreamThinkBuild on November 20, 2009, 12:55:45 PM
Lookup "Magnetic Gearing | Coupling | Transmission" in Google patents you'll find a lot of designs on this.

I'm wondering how you would go about calculating the ratio/power for magnetic gears? If you have one driving magnetic gear that is using 400lbs of force magnets and pushing a running magnetic gear that has 100lb of force magnets?

Heres a couple:

http://www.google.com/patents/about?id=sSAkAAAAEBAJ&dq=5569967
http://www.google.com/patents/about?id=qv8wAAAAEBAJ&dq=4167684
http://www.google.com/patents/about?id=ArkyAAAAEBAJ&dq=3814962
Title: Re: Magnetic Gear
Post by: gravityblock on November 20, 2009, 01:40:35 PM
Halbach Arrays are also used in magnetic coupling.  Magnetic coupling devices transmit torque through magnetically transparent barriers (that is the barrier is non-magnetic or is magnetic but is not affected by an applied magnetic field), for instance between sealed containers or pressurised vessels.

The optimal torque couplings consists of a pair of coaxially nested cylinders with opposite +k and -k flux magnetization patterns, as -k magnetization patterns produce fields entirely external to the cylinder. In the lowest energy state, the outer flux of the inner cylinder exactly matches the internal flux of the outer cylinder. Rotating one cylinder relative to the other from this state results in a restoring torque.
Title: Re: Magnetic Gear
Post by: Azorus on November 23, 2009, 12:37:29 AM
Thanks for all the replies!  I was thinking though, if you have a CD spindle with all north facing magnets and another all north facing magnets, if you push them together where they align inbetween each other but still repel each other wouldn't that work?
Title: Re: Magnetic Gear
Post by: gravityblock on November 23, 2009, 02:51:25 AM
Quote from: Azorus on November 23, 2009, 12:37:29 AM
....if you have a CD spindle with all north facing magnets and another all north facing magnets, if you push them together where they align inbetween each other but still repel each other wouldn't that work?

If it's setup like this video http://www.youtube.com/watch?v=IlUY3snoWI8 , then no.  The ring magnets in the video are in attraction mode.  It wouldn't work in repel mode either.  When axial magnetized magnets rotates on their magnetic axis, then the magnetic field remains stationary.  This is Faraday's Paradox. 

A magnetic stirrer would work.  All you need is a pc fan, two round axial magnetized magnets or 1 radial magnetized magnet, and a magnetic stir bar.  You don't need all the circuitry that is in the video, that is for adjusting the speed.  With the magnetic stirrer you can have your own yeast starter for home brewing or for making colloidal silver and other purposes.  http://www.youtube.com/watch?v=uPgLMeQb7c8

Two circular halbach arrays aren't difficult to build.  This would give you the best magnetic coupling.  Here's how to build your circular halbach's, http://www.youtube.com/watch?v=CjTOegBTSV0

Edit:  Axial magnetized magnets have poles on the opposite sides.  North pole on the "tails side" and south on the "heads side".  Radial magnetize magnets have both a North Pole and South Pole on the same sides of the magnet.
Title: Re: Magnetic Gear
Post by: Azorus on November 24, 2009, 02:55:33 AM
Thanks! Answered my question