Seen advertisements where the ferromagnetic cookware used on induction cooktops turns the cooktop power off when pulled away from the 'burner' by some built-in sensor. Am fine with that.

 

If the energy is magnetically transferred to a ferromagnetic pot; how can the pot be effortlessly lifted without the attraction force impeding the action ? How does it work ?

 

Question 2 : What stainless steel alloy is more convenient for induction cookware that will be used suspended 3 mm above the induction cooktop suface ?

Seen advertisements where the ferromagnetic cookware used on induction cooktops turns the cooktop power off when pulled away from the 'burner' by some built-in sensor. Am fine with that.

 

If the energy is magnetically transferred to a ferromagnetic pot; how can the pot be effortlessly lifted without the attraction force impeding the action ? How does it work ?

I'm not sure it's effortless, but as long as it's small compared to the weight of the pan you won't notice it. It's AC, so the direction of the field is continually changing, which implies that part of the time the effect is repulsive. The pan doesn't jump off of the coil which confirms the force is smaller than the weight.

Thanks.

Of course, it is high frequency AC; but AC fed solenoids/relays/electromagnets do sustain attraction when energized. I would have to try myself if nobody else on the forum uses such cooktop.

 

Seems 340 alloy is the convenient one.

 

Of course, it is high frequency AC; but AC fed solenoids/relays/electromagnets do sustain attraction when energized.

 

 

AFAIK they are rectified or have some other circuitry to produce a similar effect. I assume this is lacking in a metal pan.

AC also attracts ferromagnetic metal. On one induction cooker I can feel it. It's weak because the induction is weak.

 

I looked at the power electronics of this particular cooker: mains enters on a single-phase rectifier without filtering inductor nor capacitor, so it still wobbles at 100Hz here, and this wobbling DC is chopped around 40kHz by semiconductors and sent to the coil, which has flat braided copper and ferrite bars below, while the pan closes the magnetic path above.