This is an improved form of direct core type induction furnace. This furnace removes all the defects mentioned in induction heating furnace.
The furnace employs a vertical crucible instead of horizontal furnace for the charge.
It has iron core similar to 3 phase transformer. The principle of operation of induction heating furnace is same as that of transformer action. Here, only difference is that secondary winding is replaced by a closed loop of molten metal.
Primary is an inductor coil wound on central limb of the laminated core which concentrates the magnetic flux.
Therefore, heat is generated in the charge by the action of heavy induced current which flows in channel of molten metal situated between an inductor coil and furnace lining.ct
Molten metal in V portion acts as short circuit secondary coil. Reversing magnetic field links with this molten metal causes circulation of induced currents.
Therefore, heat is mainly generated in the V section and is rapidly distributed to the metal by convection. The stirring action takes place by electromagnetic process.
Since, the V channel is narrow, a small quantity of charge is sufficient to keep the secondary circuit closed. Hence, the chances of discontinuity of the circuit are less.
