is shown by the sign and 34 dot 34 symbols in fig8 the ampere turns of the shorted turn comprising the molten metal sheet 34 and the conducting shield 29 have by transformer action essentially the same value as the ampere turns of the ac conducting coil 82 the ac conducting coil 82 carries an additional relatively small magnetizing current the equivalent circuit of the shorted turn comprised of the molten metal sheet 34 and the conducting shield 29 is shown in schematic diagram form in fig9 regulation of the voltage rather than the current of the magnet ac power supply 42 augments the effect of the first and second side guards 30 32 in providing vertical positioning stability for the molten metal sheet 34 the molten metal sheet 34 the magnet comprised of the u shaped ferromagnetic core 74 and ac conducting racetrack coil 82 and the ac power supply 42 form an inductively coupled circuit as shown in fig9 l sub u03c3 94 represents the inductance of the air gap between the two poles 74b 74c of the ferromagnetic yoke 74 while l m 96 represents the inductance of the magnet similarly the impedance of the molten metal sheet.