How does the induction cooker work?why aluminium pot does not work ?

In summary: He told me that non-magnetic pans are not compatible and I should only use magnetic pans. Is that true?It's safe to use non-magnetic pans, but they will not heat as well. It's also possible that the hob will not turn on at all with them.It's safe to use non-magnetic pans, but they will not heat as well. It's also possible that the hob will not turn on at all with them.
  • #1
magnetar
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0
How does the induction cooker work?why aluminium pot does not work?








Thank you in advance
 
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  • #2
It's an eletro-magnet. The field changes very quickly (20-30KHz) each cycle magnetises and demagnetises the pan, each cycle loses some energy - which goes into heating the food.
It is possible to heat aluminium with an inductor but it is less effective and needs a different frequency - I woked on a system that would heat coffee/ready meals with an Aluminium film inside the packaging and an inductor pad on the counter.
 
  • #3
In addition to hysteresis heat loss as mentioned by mgb_phys, heating occurs due to electrical resistance and eddy currents.

Changing the direction of the magnetic field passing through the cookware induces little so called 'eddy currents' which are circular loops of current due to the effect of electromagnetic induction (see Faraday's Law). In a metal with resistance, the eddy currents dissipate to produce heat because electrons collide with the metal lattice (see Joule heating).

But like mgb_phys said, there is no reason why aluminium wouldn't work. Where did you hear that?
 
  • #4
jaseh86 said:
In addition to hysteresis heat loss as mentioned by mgb_phys, heating occurs due to electrical resistance and eddy currents.
I forgot the numbers but it's largely hysteresis.

But like mgb_phys said, there is no reason why aluminium wouldn't work. Where did you hear that?
The instruction with most domestic cookers tell you to only use magnetic pans. In fact some even have a magnet sensor as a safety feature and will only turn on with a steel/iron pan present.
 
  • #6
mgb_phys said:
I forgot the numbers but it's largely hysteresis.


The instruction with most domestic cookers tell you to only use magnetic pans. In fact some even have a magnet sensor as a safety feature and will only turn on with a steel/iron pan present.

Ah okay. I didn't know that. So is it actually unsafe to use aluminium or is it just an issue of magnetisation efficiency?
 
  • #7
It's safe - but it's likely that it will have no heating effect at the frequencies used.
 
  • #8
mgb_phys said:
It's safe - but it's likely that it will have no heating effect at the frequencies used.

Just to introdce something new

I have a doubt in all these?

If Aluminium won't work if it is non-magnetic why does Stainless steel? Is it because it is almost Steel?

Also if I Earth a ferromagnetic vessel on the top of an induction stove, what will happen?
 
  • #9
vijayradnus said:
If Aluminium won't work if it is non-magnetic why does Stainless steel? Is it because it is almost Steel?
Domestic induction hobs mostly rely on magnetic hysterisis, as I said you can use eddy currents for heating Aluminium (or indeed Iron) but the frequency is different and it's not as efficent.
Stainless will work, although non-magnetic stainless is much less efficent.
In practice most high quailty stainless pans are 300 series steel (low magnetic / high corrosion resistance) and have a copper base which is not at all magnetic and so don't work on induction hobs.
The copper base is because the thermal conductivity of stainless is low.

Also if I Earth a ferromagnetic vessel on the top of an induction stove, what will happen?
If it is heating by eddy currents and you provided a low enough impedance Earth (think busbar or welding cable rather than regular electrical wiring) it would reduce the heating, it would have no real effect on magnetic hysterisis.
 
  • #10
vijayradnus said:
Also if I Earth a ferromagnetic vessel on the top of an induction stove, what will happen?

No current will flow in the ground wire. It's not absolutely zero, but close enough. More than one ground connection with fractional or whole turns around the geometric axis of the magnetic field will cause currents to be induced in the grounds.

mgb. It's likely turn-on is prevented against the low load condition presented by resistive-only loads to protect the silicon drivers, rather than the safety of the operator.
 
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  • #11
Phrak said:
mgb. It's likely turn-on is prevented against the low load condition presented by resistive-only loads to protect the silicon drivers, rather than the safety of the operator.
Yes the safety of the hob was what I meant.
Some even sense the resistivity change in the pan and use this as a thermostat.
 
  • #12
mgb_phys said:
Yes the safety of the hob was what I meant.
Some even sense the resistivity change in the pan and use this as a thermostat.

Ah, I should have known. I once spoke to a technician who had been involved in designing MGBT drive circuits for stoves. I never could get much out of him, seeming that he troubleshoot by devining rod.
But this is beginning to sound suspiciously like your forte.
 

1. How does the induction cooker work?

The induction cooker uses a high-frequency electromagnetic field to heat up the cookware. This field creates an electric current in the metal of the cookware, producing heat. The heat is then transferred to the food inside the cookware, cooking it evenly and quickly.

2. Why does the induction cooker only work with certain types of cookware?

Induction cookers only work with cookware that has a high ferromagnetic metal content, such as cast iron or stainless steel. This is because the magnetic field can only generate current in materials that are capable of magnetization.

3. Can I use an aluminium pot on an induction cooker?

No, aluminium pots do not work on induction cookers because aluminium is not a ferromagnetic metal. The magnetic field cannot generate current in the aluminium, so it will not heat up and the food will not cook.

4. What happens if I accidentally use an aluminium pot on an induction cooker?

If you use an aluminium pot on an induction cooker, the pot will not heat up and the food will not cook. However, the induction cooker will still produce an electromagnetic field, which could potentially damage the pot and cause it to warp or crack.

5. Can I use any type of stainless steel cookware on an induction cooker?

No, not all stainless steel cookware is suitable for use on an induction cooker. It must contain a high percentage of iron to be able to create an electric current and heat up. Check the manufacturer's label or do a magnet test to see if the cookware is compatible with induction cookers.

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