Five-Megajoule Homopolar Upgrade

The five-megajoule homopolar generator (5-MJ HPG) designed and built in 1974 by the Center for Electromechanics at the University of Texas at Austin (CEM-UT) was the result of an engineering feasibility study that examined alternate means of pulsed energy storage for controlled thermonuclear fusion experiments. The machine proved very reliable and useful in a variety of applications, notably pulsed resistance welding, and was modified in 1978 to improve its flexibility and ease of maintenance. CEM-UT is now completing a major upgrading of this HPG to a hydraulically motored, 10-MJ, 47-V, 1.02-MA device capable of welding large-section, high-carbon railroad rail. This report considers the design and fabrication of the new rotor, shaft, brush mechanisms, field coil, making switch, busbar system, and control system, as well as the addition of the 31-MPa (4,500 psi) hydraulic motoring system. Future applications of the 10-MJ HPG are also discussed.