Pulsed High-Power Brush Research, Part III: Experiments at 15.5 MA/m2and 277m/s

High-power fast-pulsed energy transfer requirements of many proposed fusion reactor concepts have prompted interest in the use of homopolar machines with superconducting excitation as "electromechanical capacitors." At the high rotor (collector) speeds necessary to maximize their desirability, these inherently high-current lowvoltage machines have demanding requirements for their current collection systems. In addition, the high-excitation magnetic fields interact with the current to create significant electromagnetic forces on the brushes. Precise and predictable actuation of the brushes is required for these machines to be technically feasible. The design of a current collection system for such a machine is briefly described. Results achieved by testing a prototype of such a system are presented, involving brushes manufactured from four different materials run in three different ambient atmospheres.