Fabrication of a rotor for a field based, self-excited compulsator power supply for a 9 MJ railgun demonstrator

Fabrication of a high-speed, self-excited air-core rotor for a field based compulsator is well under way. The compulsator is to be used as a power supply for firing 9 MJ projectiles from a skid mounted electromagnetic launcher (railgun). The rotor flywheel is made of fiber reinforced epoxy composite and is supported with high-strength metal stub shafts which are shielded from the excitation field by water-cooled copper sleeves. The rotor features separate windings for self-excitation and railgun firing, and a two-pole configuration for pulse length considerations. The rotor is designed to store 210 MJ at 8600 r/min, with a rating of 3.2 MA peak current and 20 GW peak power into a 9 MJ railgun load. The concentric fiber-reinforced epoxy composite rings that make up the rotor flywheel are filament wound on steel mandrels, cured, and interference fit together. The main and excitation armatures and output conductors leading from the armatures to the shaft conductors are constructed of epoxy-impregnated aluminum and copper Litz wire.>