Re: [Phys-l] Inductive cooking

[Brian Whatcott <betwys1@sbcglobal.net>]

Joseph Bellina wrote:
> I just bought unit  that heats cooking pots by induction.  I assumed  
> that it would work with any pan that conducts, since I assumed it  
> worked by generating eddy currents in the pots.  Surprisingly, the  
> literature says it only works with pots that are magnetic, and even  
> provides a little magnet so you can check.  They make a point of  
> saying that  Al pots will not work and that only some stainless pots  
> will work.  I know some stainlesses are magnetic and some are not.
>
> I haven't tried using a non-magnetic pot to test the claim yet, but  
> wondered if anyone had a good idea about this.
>
> joe
>
> Joseph J. Bellina, Jr. Ph.D.

Not a good idea particularly, but a plausible thought.
In hindsight, one can imagine a magnetic steel pan carcass couples more 
effectively to a driving coil as a higher lossy reactive impedance, 
providing a better opportunity to dissipate the drive into the pan case. 
Still, a thick aluminum pan would present as a lower lossy impedance, 
increasing losses in a driver meant to work with both, but still heating up.
(The driver would run hotter, the pan would heat more slowly?)
Better to optimize on the magnetic case, and sense for this type, so as 
to switch off the drive in other more testing circumstances?

Brian W