Assembly and Testing of a Compact, Lightweight Homopolar Generator Power Supply

Abstract

Abstract : Since January 1980, The Center for Electromechanics at The University of Texas at Austin (CEM-UT), funded by the U.S. Army Armament Research and Development Command (ARRADCOM) and the Defense Advanced Research Projects Agency (DARPA), has been developing a high-energy- density, high-current power supply to drive an electromagnetic (EM) railgun. Achieving high energy density, which implies a compact, lightweight device, is required if EM accelerators are to become practical, field-portable systems. The initial step in developing the power supply was to design, fabricate and test a prototype homopolar generator, attempting to improve the state of the art in energy and power density. This step was completed in August 1982. Utilizing the All-Iron- Rotating (A-I-R) configuration, which eliminates the back-iron of previous machines, the prototype compact HPG inertially stores 6.2 MJ and weighs 3400 lbm, a state-of-the-art gain in energy density of a factor of two. During initial tests, the HPG generated a 1.02 MA current pulse. Analysis indicates that one compact HPG will drive an 85-g projectile to 3 km/s in a 4-m gun or a 10-g projectile to 10 km/s in a 5.5-m gun. The machine is currently being upgraded, and a compact inductor is being built to provide a load. This paper summarizes the machine design, presents results of the initial test sequence, and briefly discusses the continuing CEM-UT program to develop a high-energy density, high-current EM railgun power supply.