Binary Nitrogen-Cooled 10 kA Leads

A pair of binary current leads has been constructed with a nitrogen vapor cooled resistive section and a stainless steel shunted HTS lower section. These leads are intended as replacement leads for the NHMFL 45 T Hybrid and also serve as half-current prototypes for the 20 kA leads foreseen for the Series Connected Hybrids that are under development at the NHMFL. An amount of liquid nitrogen is maintained in a reservoir at the bottom of the resistive section such that vapor flow is determined by self- demand. The liquid nitrogen delivery system and properties of the vapor cooled section of the leads are described. A comparison is made between the measured and calculated properties of the resistive section in steady state and transient conditions.