The Design, Fabrication, and Testing of a Five Megajoule Homopolar Motor-Generator

Abstract

The current and future generations of controlled thermonuclear fusion experiments require large amounts of pulsed energy for heating and confinement of plasma. Kinetic energy storage with direct conversion to electrical power (i.e. homopolar machines) seems to be the most economically attractive solution for meeting these requirements.

The University of Texas at Austin has a program intended to develop a design technology for homopolar machines to meet a broad spectrum of performance requirements in terms of stored energy and discharge times. The Energy Storage Group at the University of Texas at Austin has in the past ten months designed, fabricated, assembled and begun a thorough testing program on a second generation homopolar machine with a storage capacity of five megajoules. This machine, using room temperature field coils, solid electrical brushes, and hydrostatic bearings has been designed to deliver 42 volt pulses at current levels in excess of 150,000 amperes. The machine has been designed as a laboratory device with extremely stiff bearings, variable brush area as well as variable brush contact force, variable field strength for pulse shaping, and minicomputer controlled data acquisition, real time signature analysis and on line experiment control. A continuing program studying discharge characteristics, brush and rotor dynamics, machine losses, and system efficiencies is already underway and is currently funded through June, 1975. Funding for the project has been provided by the Atomic Energy Commission, the Texas Atomic Energy Research Foundation, and the Electric Power Research Institute.