magnetic drag brake

[kinarfi]

First time here, hope I'm in the right area!
I have several very strong magnets out of computer hard drives and I am thinking of using them to create a drag brake for my off road vehicle by holding them close to the rotating drive line. I don't think the walls of the drive line may be too thin and my question is, if I wrap the drive line with a long sheet of aluminum, will the fact that it's layered reduce induced magnetic eddy currents and diminish the drag.
I was thinking to put flat disk around the drive line, I think just getting the magnets close to the drive as it spins will do the job.
If you have any advice, I would sure appreciate your help!
Kinarfi

 

[EdStainless]

How much drag are you trying to generate?
Remember that all of the energy that you put into this device will end up as heat.
These brakes get very hot unless cooled actively.

They are usually magnets on either side of a disc, ala disc brakes.
This help dissipate the heat.


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Plymouth Tube

 

[kinarfi]

Thank you, that is one of obstacles I was concerned with. Is there a good place to go to for information with out it getting too technical? Is it better to have thick metal than thin, is better to have solid rather than layered metal. I was hoping to create enough drag to slow my off road vehicle down when going down hill so I wouldn't need to use my brakes or gearing so much. Ideally, I would use an electro magnet as my magnetic source which could be actively controlled with feed back. My vehicle weighs about 2500 lb with me & my wife in it.
Thanks,
Kinarfi

 

[EdStainless]

There are commercial built electromagnetic drag brakes that are using in industrial applications. They are typically used for providing controlled back tension, such as on a roll of paper as it is being unwound and fed into a machine.
Try a google search.

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Plymouth Tube

 

[kinarfi]

I thoughts, now, are to put a row of neo magnets along side the drive line, thus distributing the heat over a relatively large area. The drive line is steel, so do you have any idea of how that will effect the drag? Will the magnetic attraction cause the magnets to pull in close and make contact or will the generated current cause them to repel?

 

[IRstuff]

Brake disks are sized to accommodate the required braking load. Your drive line is so small a radius that you would likely need a swath 10 inches wide filled with magnets to make this work.

TTFN
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