Questions about magnets.

[eugenebrooks]

Originally Posted by Elgin Clock

What is the most effective way to shield from magnetic fields?

High permeability material, sold under the trade name "mu metal"
is used to shield magnetic fields.

[Al Skierkiewicz]

Originally Posted by eugenebrooks

High permeability material, sold under the trade name "mu metal"
is used to shield magnetic fields.

Gene,
Do you have a source for mumetal, we are almost out of the sheet stock and I need to replenish but have only been half hearted about looking.

Ferro fluid is not a magnet it is ferrous metal particles suspended in a viscous liquid. It is most commonly used for speaker voice coil cooling. A few drops squirted into the gap between the voice coil and the magnet structure will do a great job of transferring heat to the magnet body and basket assy without changing the damping of the speaker.

[Greg Young]

That stuff is really cool. I saw on TV something sort of like that which they were developing to use as fluid in off-road racing shocks to essentially change the viscosity in a matter of miliseconds.

Lord Corporation (http://www.lord.com/Default.aspx?tabid=718) has been developing magnetorheological fluid applications for several years. The site has lots of interesting information and applications.

There must be a way to make a continuously variable transmission for a FIRST robot using this stuff, but I haven't come up with one yet.

[Andrew Blair]

Originally Posted by Greg Young

Lord Corporation (http://www.lord.com/Default.aspx?tabid=718) has been developing magnetorheological fluid applications for several years. The site has lots of interesting information and applications.

There must be a way to make a continuously variable transmission for a FIRST robot using this stuff, but I haven't come up with one yet.

Well, Lord is located near us, and at a career fair I got to play around a bit with it. I cannot imagine a way that you could make a CVT with it, but a magnetic clutch is very feasible. FIRST or otherwise, it'd make for some nice shifting tranmissions!