LordKitchenersValet
7135
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2
Sep 23, 2024 12:35 PM
LordKitchenersValet
7135
55
2
TheGrunk
DoctorPitt
a visual guide to my body processing tacobell
Canigetbannedagain2
Isn't that a an inductor coil?
delpharseven
Much longer version from the old times: https://youtu.be/8i2OVqWo9s0
Frenchgeek
Why you must be very careful when choosing your magical girl candidate.
MajMalfunction2
I don't think that's aluminum.
LordKitchenersValet
It is; it's just a funky way of melting/levitating it using induction rather than magnetism, as I understand it:
https://www.ambrell.com/induction-heating-applications/levitation-melting
YuffieK
Induction smelting: https://en.wikipedia.org/wiki/Induction_furnace
T3sl4co1l
Close; smelting is reducing ores to metal. It's just regular melting when it's already metal.
SilentSecretMan
That’s hot
Trollero
Put... put your rod in it
MoonMoon89
I think molten metals are less affected by magnetic fields. I think. Maybe. I googled it once a few years ago for science.
T3sl4co1l
Sort of. No magnetic materials are magnetic anywhere near their melting point, so plain old induction (eddy current) heating gets it there. Resistivity either...steps up, or changes slope? when melting, which means more voltage is required, which changes the tuning of the induction power supply.
T3sl4co1l
Copper for example is a wild one, starting at room temperature with the same conductivity as the coil around it (so, heating efficiency is piss, most of the power goes into the thinner coil than the bulk metal workpiece). As it gets to red hot or so, resistance rises enough that it's an okay heating target, and efficiency is good. If you're operating in a power limit, the heating rate visibly accelerates as the efficiency goes up.
3rdoption
I'm confused. Isn't aluminum non-magnetic?
petresun
No. But it's conductive.
mbq7
Al is paramagnetic, it will get magnetic in a strong field; but here the coil just induces current in the piece, and this current is responsible for the lift. Melting probably destabilises the whole thing mechanically, but I'm not sure about that.
bobbobbybobbington
it's not ferrous (ie it cannot be picked up with a magnet) but due to it's conductance any changing magnetic field will induce motion in the electrons, and thus create a magnetic field (moving charges create an electromagnetic fields)
The coil alternates current (and thus magnetic field) rapidly, the electrons in the material thus have to keep changing direction, keep generating a response M field, and also lots of heat.
LordKitchenersValet
I'm confused too. I read this:
https://www.scienceabc.com/eyeopeners/why-are-some-materials-magnetic-and-is-aluminum-magnetic.html
And I decided that Monday morning is not time for me to try to understand new science. : ) My best guess is that aluminum is semi-magnetic (er, "paramagnetic") in certain circumstances
LordKitchenersValet
https://en.wikipedia.org/wiki/Paramagnetism
Paramagnetic materials include aluminium, oxygen, titanium, and iron oxide (FeO). Therefore, a simple rule of thumb is used in chemistry to determine whether a particle (atom, ion, or molecule) is paramagnetic or diamagnetic: if all electrons in the particle are paired, then the substance made of this particle is diamagnetic; if it has unpaired electrons, then the substance is paramagnetic.
T3sl4co1l
Yep, but mind that para/diamagnetism is an extremely weak effect for most materials; parts-per-million sort of range. So it's easy to ignore in most cases. Even the magnetism of normally-nonmagnetic stainless steel (say 304 or 316 alloy) is stronger, particularly when work hardened. To levitate something using this effect, you need truly monstrous fields! This was I believe 30T or so:
CookyMonster42
Maybe it's an alloy containing ferromagnetic components, but not sure if that would have such an impact
CookyMonster42
Or not aluminum at all
T3sl4co1l
Not a bad thought -- but iron is soluble in aluminum, so if it's a homogeneous alloy (like most in use), it'll be present as a compound (intermetallic) instead -- mixtures of Al, Fe, Si and Mg most often, which aren't magnetic. You could have chunks of undissolved iron (inhomogeneous / non-equilibrium alloy) bonded together by an Al matrix, which would be magnetic though!
YuffieK
It just has to be electrically conductive. The eddy currents from the coil will levitate it.
YuffieK
Dropping a magnet down a (non-magnetic) copper pipe:
battleofhastings1066
Everything reminds me of her.
coothlesscthulhu