what is the principle on which induction heater functions.?

Question

while cooking, it does not heat the utensil. It only cooks food.
Without heating the utensil, how is it possible to cook food in the utensil? Without any contacts between the heater and food to be cooked, how does heat radiates?

Answer 1

The concept of heating without any physical contact is induction heating. The basic principle behind heating by induction is that a very strong rapidly alternating magnetic field will induce eddy currents on any conductive material placed in the vicinity of that field. These eddy currents than heat the metal by induction. The amount of heating will depend on the field strength (and thus the amount of power running through the heating coil and how far it is from the material being heated), how quickly the field is changing (the heating coil power supply frequency), and the degree of coupling between the coil and what is being heated (how close the objects are to one another, what their geometry is).

Maximum temperature achieved will depend on how much power is going into the heating process and how much power radiates out of it. Higher powers with larger degrees of coupling and high frequencies will heat up materials faster, but higher frequencies will also cause heating to be shallow.

Answer 2

In fact, the inductive heating DOES heat the utensil (that is, the metal pot that contains the food, or in some cases a metal radiator that is immersed in the food).

The surface on which the pot is placed, contains an induction coil which generates a rapidly changing magnetic field. This in turn induces electrical currents inside any nearby metal. The electrical resistance of the metal causes the electrical currents to turn into heat. The heat radiating from the metal utensil then heats the food.

Answer 3

Take a look at the following, hope it helps:

http://www.inductionsystems.com/induction_cooktops.html
http://eartheasy.com/article_induction_cooking.htm
http://www.dvorsons.com/Iwatani/Induction.html
http://www.divainduction.com/articles.php?article=1