.

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There you go Cool find!

That's not quite right. There are no magnets here, only magnetic fluxes. There is a high frequency AC in that copper piping which induces currents in the metal.

Google induction heating.

That's just a standard induction coil. It does use energy about the same as a welder. Depending not he size obviously. It is designed to generate heat, but a by product is a magnetic field. Very common in manufacturing. My neighbor makes screws and use them I his machines to preheat the metal before it enters the stamping machine.

gotta put the video id between the

It clearly says "melting metal with magnets" so it is a misleading title. I'm in Chippewa Falls (ask teh google maps)

The material in the induction coil looks to be a magnet... I don't imagine a piece of metal would have sufficient weight to hover in the coil like that. But at that temperature you would think, that it would loose its magnetism? Right?

bobhaha said:

The material in the induction coil looks to be a magnet... I don't imagine a piece of metal would have sufficient weight to hover in the coil like that. But at that temperature you would think, that it would loose its magnetism? Right?

Click to expand...

Its a peace of aluminium , The magnetic field inside a induction heater coil is enough to levitate small pices of light aluminium , and sometimes copper .

Due to the such large eddie currents in the aluminium and being diamagnetic , the magnetic field it creates repels the field the work coil makes , thus is levitates .


Only downside is , if its series resonance by design , if the work pice falls out the work coil , without current control on the inverter due to the resonant effect the currant drawn from the supply sky rockets and IGBTs don't like it . Ive been there once as I tried it with my 2kW induction heater I made a while back , RIP IGBT

Yes it would loose it's magnetism, a while back I needed to solder wires to a small round 2mm dia magnet and that small amount of heat killed the magnet

bobhaha said:

The material in the induction coil looks to be a magnet... I don't imagine a piece of metal would have sufficient weight to hover in the coil like that. But at that temperature you would think, that it would loose its magnetism? Right?

Click to expand...

Flaminpyro said:

Yes it would loose it's magnetism, a while back I needed to solder wires to a small round 2mm dia magnet and that small amount of heat killed the magnet

Click to expand...

If you can solder fast enough, you can make Tcurie (temperature that the materials lose their magnetic property) higher, by putting some metal around the magnet while soldering. I had a link for that.....

edit: http://myip.cctec.cornell.edu/index.cfm/ts.details?tk=K4AB2317153854938841

I always thought that the high heat and alternating field
would kill a magnet. That AC field should be bad news to
a magnet -- that's how we used to "clean, de-mag" a tape recorder
head.
HMike

Why is no one listening? ionlaser is correct. It's not a magnet - it is a piece of Al bar stock.

ionlaser555 said:

Its a peace of aluminium , The magnetic field inside a induction heater coil is enough to levitate small pices of light aluminium , and sometimes copper .

Due to the such large eddie currents in the aluminium and being diamagnetic , the magnetic field it creates repels the field the work coil makes , thus is levitates .


Only downside is , if its series resonance by design , if the work pice falls out the work coil , without current control on the inverter due to the resonant effect the currant drawn from the supply sky rockets and IGBTs don't like it . Ive been there once as I tried it with my 2kW induction heater I made a while back , RIP IGBT

Click to expand...

Wow... ok, I just didn't think the coil would hold it in place like that. I would have imagined it would want to pass through the coil, like how a solenoid works. It seems to sit inside the coil.

Another interesting thing is, it didn't pool up into a ball because of surface tension, instead kind of spread out vertically. I find that interesting.

Cyparagon said:

Why is no one listening? ionlaser is correct. It's not a magnet - it is a piece of Al bar stock.

Click to expand...

I am :na:

I think solenoids work by pulling metal into the coil, not through it.

One reason it levites is due to the fact that the work coil , isn't a cylinder , its more cone shaped with the inner diameter getting samller as you get to the bottom and the very top turn is in the opposite direction to the rest of them .

Due to the smaller hole under the aluminium slug , the magnetic field is trying to push the aluminium up , but as the other turn at the top is in the opposite direction , its field will try and push the aluminium down , now the field under and around the aluminium is stronger than the one pushing it down , but do to the weight of the aluminium , its just " levitates "

I have made a small one. It is not simple or easy by any means, for the reasons ionlaser
has said and many more, and is much different from a regular arc welder. Flyback drivers
and tesla coils are much easier to build. I suggest being experienced by those before
attempting something like this.

To illustrate the differences between this and a regular welder, let's begin with just the
basic way a welder works. An arc welder uses high temperature plasma to melt a small
area of metal. Current flows from the welder directly through the piece of metal.

An induction heater induces an eddy current into a piece of metal electromagnetically
without any contact. The heat is spread out over a much larger area. This makes it
difficult or impossible to weld metal with an induction heater. The whole piece will begin to
melt.

Another difference is in the type of power. Welders use DC or AC frequencies below 1kHz.
Induction heaters have to use frequencies of many kHz or MHz. This imposes design
constraints over and above those of a welder. There are special capacitors, diodes, liquid
cooling, and even component placement is important.