ELECTROMAGNETIC LEVITATION CASTING APPARATUS HAVING IMPROVED LEVITATION COIL ASSEMBLY

摘要

An electromagnetic levitation casting apparatus having an improved levitation coil assembly employing flux concentration devices, is provided. The improved levitation coil assembly comprises a plurality of slotted annular slugs surrounding a tubular casting vessel within which a liquid metal column is to be levitated and solidified by cooling pursuant to the General Electric Levitation Casting (GELEC (TM)) process. Each of the slotted annular slugs is inductively coupled to a respective electromagnetic field producing coil having a large number of turns surrounding the slug. Each slotted annular slug serves to concentrate the magnetic field produced by its associated primary multi-turn coil to substantially the interior cross sectional area of the tubular casting vessel it surrounds and functions as a current step-up transformer. A separate slotted annular slug and associated surrounding electromagnetic multi-turn field producing coil is provided for each phase winding of the multiphase excitation employed in the improved levitation coil assembly.