Induction Heating

When alternating current flows in a ferromagnetic material it gets heated up by the eddy  currents. It cans be easily compared with a transformer. In the transformer by electromagnetic principle  electrical  energy  transferred from  primary  to secondary of transformer it is used when  a load is  connected in secondary  side.  Here we say that in  induction heating the  energy  transferred from  primary is directly  utilized in the secondary.

                                                              figure Solid metallic cylinder heated by  induction  heating

Consider a long solid  metallic  cylinder which  is heated by  a long helical coil  wound  over it  in account  of analyses the factors  the  affecting  induction heating let number  or turns  over the  metal  piece be N length  of coil be I  meters and the resistivity  of the material be e r. M.

When an alternating  current I1 of frequency f flows  in the coil  an alternating flux  ? is set up. The  direction of this  flux is  along  the axis  of the coil.  An induced emf product  in the coil  which  is responsible  to flow  the eddy  current in metal piece. The power loss of eddy current in the metal piece produces heat. Here we  can assume that if  material to be heated acting as one  turn secondary then the ampere turns of primary  should be equal  to that  of secondary .

I₁ N₁ = I₂ N₂

But N₂  = 1 so  we can take N₁ = N

Hence I₁ N = I₂

Power  loss in  secondary  P = I₂²R

Where R = resistance of the metal piece.