Current leads for cryogenic applications are designed to transmit large currents from room temperature to the very low temperatures of superconducting coils.  They are used in applications such as NMR and MRI magnets, beamline magnets and driven (non-persistent) magnets.  Current leads that are good electrical conductors are also good conductors of heat, but for cryogenic applications, current leads must minimise heat in-leak whilst safely carrying the design current.  Liquid-helium cooled superconducting magnets typically achieve this by using vapour-cooled leads. For cryogen-free LTS and HTS magnets however the benefit of HTS current leads is a dramatic reduction in thermal conduction and the elimination of resistive heating over the HTS section of the lead.  Compared to copper, HTS offers a reduction heat conduction by a factor of 10 and in large installations the benefit of HTS current leads has been estimated at approximately 20% of the total thermal budget. About HTS-110 Current  Leads

CryoSaver™ second generation of current leads, CryoSaver™ II, rated from 150A to more than 2000A, deliver significantly improved performance with lower heat leak, reducing heat load and losses for client’s systems. We achieve this by using 1^st generation BSCCO wire with an alloyed matrix to minimise thermal conductivity. HTS-110 Cryosaver™ current leads are designed to fit within the cryogenic environment.  They are perfectly suited to operation between the 1^st and 2^nd stage of crycoolers.

Leads are available in a number of formats:

Standard and short leads

Standard CryoSaver™ leads use a fibreglass composite body to encase the HTS wire for structural integrity. Nickel plated copper end caps are used for warm and cold end connections. Shorter versions of standard current leads are available for space constrained applications.

Customisation

CryoSaver™ current leads which include custom terminals, specific dimensions, complex geometry and high current (>10kA), can be designed and manufactured to meet client requirements.

Ballasted leads

These incorporate a current shunt in the lead body to protect inductive loads in case of lead quench.  Length, terminal design and current capacity can be customised at the time of order.

Sapphire Heat Sink Kits       

HTS-110 has developed Sapphire Heat Sink Kits for use on standard length leads to optimise the thermal contact between the leads and heat sinks. HTS-110 recommends the use of these with all current leads.  One kit is sufficient for a pair of current leads of less than 1000A.  Four kits are required for a pair of current leads of 1000A plus.