Hello /diy/. I got this coil out of an induction cooktop. What

>>1237920
You could make an induction Cooktop.

https://youtu.be/k4xsqw463Hs
https://youtu.be/Q6Zrnv4OtbU

>>1237920
Charge your phone.

>>1237920
Not much use for electromagnetism unless you want to unbraid all those loops and put it back together in a fundamentally different configuration.

The whole point of that setup you have is to generate heat via passing current through a resistive element.

You could strap a fan onto it to blow heat off the coils and make an effective fan heater. But you'll have to manage the contact heat on the unit to avoid parts melting each other, plus you'll basically have a big unshielded electrified lump of copper sitting there. Not so safe.

>>1237937
Also could strap it on the bottom of a metal drum to make a crude water heater/boiler.

Thing is, if you're not familiar with this stuff already you probably don't want to touch this. 110/240v kit isn't worth fucking with unless you already know your shit, in which case you wouldn't be asking what you could do with this.

>>1237937
>>1237941
That thing won't have more than a couple of ohms of resistance maximum, no way will it be practical to use as a resistive element without some sort of "core" to induce eddy currents in. You almost certainly have to put in fairly high frequency to get those to work, they probably run off rectified switched mains.

ITT: anons who've never heard of an induction cooktop
>>1237937
>>1237941
hint: those wires don't get hot - only the ferrous material placed next to it does (by induction)

>>1237951
induction furnaces here we come!!

>>1237983
How feasible are they for a homemade electric furnace? Provided you can cool the coils in water while keeping the melt hot, the coils will never decay, but the amount of magnetic flux that isn't doing anything is bound to make the furnace less efficient. I guess you'd use aluminium coils for their inertness and run a water jacket over them, but insulation will be a problem while retaining high magnetic permeability.

>>1237995
>How feasible are they for a homemade electric furnace?
Why don't you build one so you'll know for certain.

>>1238034
Looking online they're actually pretty simple and have been done before, they consist of a coil (10 or so turns) of small copper pipe which water can be run through for cooling, and some sort of high speed MOSFET inverter.

>>1237937
That's not at all how an induction cooktop works. It generates a fluctuating magnetic field that vibrates the iron in the pan that you are cooking in. The cooktop doesn't even get hot, only the pan.

>>1237947
a ham radio op documented how he made a rf dummy load of 4 cooker elements in series. apparently each was about 12 ohms so he was close to the 50 ohm load of a transmitter.

>>1238165
>that vibrates the iron in the pan
That's not quite right, friend.

You could scrap it for the value of the copper. Probably a couple bucks worth.

>>1238213
Okay so I oversimplified the concept of hysterisis heating, which only occurs in iron and is only a component of the heating. You're right, it's mostly eddy currents and resistance.

>>1237920
Put it over your grandpas pacemaker and turn it on

>>1237921
/thread

>>1238165
For safety's sake I will point out the the Cooktop surface DOES get hot while in use. Not from the induction, but by means of being in contact with the bottom of the pan, which is very hot.

True, it won't heat up without a pan on it, but you should never touch it after cooking on it, since it will be extremely hot.

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>>1238207
Interesting, have a link? A dummy load has no inductance. Pic: top from OP's image, bottom from a patent. Do the windings reverse direction? Bifilar?

>>1238246
OP's coil might simply have two layers (top and bottom).

>>1237920
A jetpack

>>1237951
Fun fact. Alluminium is generally treated as non magnetic... but foil is so thin that the induction field completely penetrates it and will melt it right into your 3k induction cooktops glass... it is not covered by any manufacturer warranties...>>1238223

>>1238228
Why don't they just suspend the pots on ceramic feet? I don't see any reason to stick with the "my cooktop is a piece of postmodern minimalist art" garbage aside from the ease of cleaning. How much clearance is there between the coil and the pot usually? I see why they use tempered glass, but there must be better materials. Ferrite would work great provided the insulated particles of iron are small enough to not be effected by hysteresis at that frequency, but I don't know how heat tolerant the stuff is. Laminations are probably too prone to high frequency hysteresis.

>>1238351
If there was an air gap it would provide an extra surface for the pot to lose heat from. Air between the pot and the surface would be heated and convect heat out of the system, decreasing efficiency.

I suppose the best material to use would be something like the ceramic they use on the space shuttle which would cool down very quickly and not conduct much heat, but tempered glass is already pretty good and like you said, easy to clean. No great need to change it.

>>1237920
Return the copper implement to its rightful owner, Jamal

>>1238354
I'm not a fan of tempered glass, it heats up significantly when frying and it scratches after a few years of use.

>>1238421
There's only so much you can do, I mean, tempered glass is very scratch resistant compared to most materials and isn't very thermally conductive.

Ceramic is the only thing I can think of thst would do better for those, but then you lose a lot of impact resistance.

>>1238424
Agreed.

If you get another coil you can do inductive power transfer, turning it into a gapped transformer.

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>>1238247
>two layers (top and bottom)
Something like that. There are different types of coils, one is the flat tightly wound kind and another has a spaced and interlaced winding that allows better cooling of the copper conductor. It resembles the twisted pair used in LAN cables but in this case the twist length is one turn and the cross-over is at a common angle.

>>1237920
Primary winding for a Tesla coil?

>>1238816
Might be a few too many turns for a small hobby-size coil, but if he's really trying to output a lot of power then yes.

Also cold he just squash the wire and soak it in a little flux for some solder wick?

>>1238657
Yes it has two layers, one above the other.

>>1237920
Yes

>>1237920
Connect the two leads directly to your headphone and listen to the sound of all kinds of devices.

>>1240185
You usually need an opamp, but with that size of coil you could probably do it with a high Z earphone, like a crystal earpiece.

File: free hot air.jpg (71KB, 1152x648px) Image search: [Google]

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Perpetual energy hot air balloon.

12v solar array, small inverter, small fan, battery, large balloon.

>>1240208
You didn't try it, I did. You need no memeamp because source and load are both low-Z. Connect left and right channel to mono. You will be surprised to hear what a laptop sounds like or a switch-mode power supply.

only about 5 posts in this thread know what induction is

i would rewind it in a tight helical circle to make an induction heater for metal work. but thats just me.

>>1237927
those are water cooled coils that have self adjusting reactance to maintain resonance and a power bank to pump huge amounts of current.

a cooktop won't have nearly the same effect.
ever see an iron pan glow on a cooktop?

>>1240298
I made an Elektrosluch, I know what they sound like, I'm just surprised that those inductors are so powerful. How much inductance do they have?

>>1240614
Induction hobs probably do adjust their frequency to remain in resonance it's more efficient for the sake of a bunch of silicon, just they're not putting multiple kW into the pot.

>>1240642
Is 2kW multiple kW? A lot of induction hobs will do 2kW in their biggest element.

>>1240733
Shit, really? I assumed it was less because they're apparently more efficient, but then again my induction hob does have the dreaded "boost" button to one side that once delaminated a pan's inner copper layer. Heat pump elements with overunity coefficient of performance when?

>>1240798
On 2kW they're very powerful, they'll boil water faster than gas, at least in my experience. About 800W to hold water at a boil for cooking pasta.

The only reason they're more efficient is because they don't waste as much power heating the coil and the rest of the stove, instead putting a higher percentage of the power directly into heating the pot. It still takes multiple kW of power to heat a pot of water to a boil in any reasonable amount of time.

>>1237921
Make a terra cotta pot smoker