Conductive Carbon Fiber
Most recent answer: 05/20/2013
- Josh (age 34)
The coils in those electromagnets have to conduct electricity. If they're made out of very good conductors, then they won't heat up too much from the electrical current. (The heating power is I2R, where I is the current and R is the resistance, which goes as 1/conductivity.) Metals are good conductors, and some (silver, copper, aluminum) are especially good. Plain carbon fibers can also conduct (see ) but not as well, so they would make poor magnet coil wires. I've read that some commercial carbon fibers have been treated with a coating that makes them very poor conductors.
Mike W. (posted without checking until Lee returns)
(published on 05/20/2013)
Follow-Up #1: conductivity and magnet wires
- Josh Oertle (age 34)
That efficiency issue is a big deal. A good electrical motor is highly efficient. Using resistive wires would wreck that. For electromagnets, using very resistive wires would reduce the attainable fields to the point where the magnet would not be of much use. In order to get large fields sustainably, for example, MRI machines use superconducting wire, with zero resistance. Even copper wouldn't be nearly good enough.
Some carbon nanotubes can be great conductors on a microscopic scale. (see ) Getting them linked together into a usable wire is a tough engineering challenge.
(posted without checking until Lee returns)
(published on 05/21/2013)