 The
electromagnetic stirrer utilizes the principle of a linear motor and
differs　from the conventional mechanical and decompression types as
it is a noncontact stirrer in which no part touches the molten metal.
As shown in the diagram, a coil installed at the bottom of the furnace
generates a moving magnetic field (H) if a 3 phase AC voltage is applied
to this coil (inductor). Electric power force is generated in the molten
metal due to the action of the magnetic field (magnetic flux) and causes
induction current (I) to flow (Fleming's right hand rule). This current
then acts with the magnetic field of the inductor to induce electromagnetic
force (F) in the molten metal according to Fleming's left hand rule.
As this thrust moves in the direction of the moving magnetic field,
the molten metal also moves. In other words, an stirring action is applied.
Furthermore, as this thrust has components in the horizontal direction
and in the vertical direction, the molten metal flows diagonally upwards
and results in a uniform temperature in both the top and bottom layers
of the molten metal. |
　
| Top | Electromagnetic
Stirrer top |
|
