Vital support systems for liquid metal collector homopolar machines

High current density homopolar machines which employ current collectors containing a liquid metal, such as NaK, require critical support systems to guarantee long term machine operation. This report describes experimental results concerning materials compatibility, liquid metal recirculation and purification systems, and the inert, protective cover gas systems necessary for machine operation. Experimental studies, as well as operation of a 3000 HP, 107,000 ampere, 20 volt, dc homopolar generator have demonstrated the necessity of such subsystems to continued machine operation.