Design study and production of the ROD inductors for bolts heating

Abstract

Based on a specific need of ŠKODA ENERGO Ltd., Plzeň, our research programme was focused on the design and manufacturing of water-cooled rod inductors; the appliance should be exploited in a heating procedure of massive ferromagnetic steel bolts. It consists of a copper U-shapped hollow conductor with an inserted ferromagnetic laminated core. Special developed thermal isolations of the copper tube conductor and the ferromagnetic core are based on polyimide and glass materials. Magnetic fields and losses were evaluated by the help of standard Rosemberg method and checked by a 2D numerical calculation. The size and geometry of the ferromagnetic core was calculated to reach the demanded induced losses in the bolt-massive material. The inductor is power supplied from a 4 kHz frequency source. The developed appliance was proved to meet successfully both the demanded induced output and heat resistance of the insulation.