Further Studies of a Low-Melting Point Alloy Used in a Liquid Metal Current Collector

Low-melting point bismuth-based alloys are potential replacements for NaK
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as liquid metal slip ring material because of their lower reactivity and potentially greater hydrodynamic stability. This paper describes experiments of one such alloy in a model of a 300-kW superconducting homopolar motor using close clearance braid-type collectors. Slip ring tip velocities varied from 5 to 20 m/s and currents ranging from 500 to 2500 A. Viscous power losses tend to follow a simple turbulent model. In all, the data supports the use of low-melting point alloys (LMPA) us an alternative to NaK
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.