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Q & A: hot electromagnets

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Most recent answer: 10/22/2007
The wire used in electromagnets heats up as electricity flows through it, right? Is there a way to insulate this heat (so it won’t set anything near it on fire) but not change the magnetic field created?
- Allison (age 13)
Tonasket, Washington, USA
Good question. The heat is not only a problemm for nearby things but also for the wires and their insulation. One of the most common techniques for keeping magnets cool is to have some cooling tubes built in, with water or some other coolant piped through.

Mike W.

By the way, for a given number of turns in the coil the magnetic field is proportional to the current, I, in the wire. The heat generated in the wire is proportional to the current squared times the resistance, R, of the wire.  So if you want to reduce the heat, reduce R.  Since the resistance is inversely proportional to the diameter of the wire squared use a larger diameter wire. (If there's enough room for it. mw)

(published on 10/22/2007)

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