[FoRK] Killer magnets

Ken Meltsner meltsner
Fri Aug 19 10:41:52 PDT 2005

"Draw their power from liquid helium" -- the reporter needs a quick
lesson on superconductivity:

The power just keeps going around in circles because the magnet wire
is superconductive -- zero resistance.   They don't want to drain the
He because, I suspect, because it would be wasteful and there'd
probably be various mechanical effects (i.e. low cycle fatigue damage)
as the wire was brought up to room temperature.  The loss of
superconductivity in a fully charged magnet (IIRC, a "quench") would
also mean that a lot of electron motion would suddenly be converted
into heat, and I'd bet that isn't good for the magnet, either.

What they need to do:  figure out how to connect the magnet wire to an
external load so that they can drop the magnetic field without warming
anything up. There's got to be an easy way to do this, or they'd be
hosed every time the magnet needs maintenance.

Ken Meltsner

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