American Magnetics Current Leads for Cryogenic Systems Brochure - Manual

Current Leads for Cryogenic Systems
P.O. Box 2509 • 112 Flint Road • Oak Ridge, TN 37831-2509
Phone: (865) 482-1056 • Fax: (865) 482-5472
E-mail: [email protected]
American Magnetics Inc.’s (AMI) Vapor Cooled Current Leads
provide reliable and consistent electrical current transfer from
room temperature (300K) to a Liquid Helium environment (4.2K).
These high efficiency heat exchangers use the heat capacity of
cold helium vapor to counterflow the incoming conductive
and resistive heat, thereby minimizing the liquid helium
consumption. The thermal input of the leads is carefully
designed to insure that just enough helium gas is generated
to provide adequate cooling across the full range of operating
currents. AMI offers a wide range of current lead designs from
small current requirements to over 100,000 Ampere leads.
FEATURES BENEFITS OF OWNERSHIP
Ultra hi-efficiency Minimize helium usage
heat transfer and operating costs
Custom designs up
Application flexibility
to 100,000 Amps
Conventional Copper Leads Proven reliability
Lower helium usage in “standby”
Brass Leads
mode without intervention
Lowest helium usage available in
Hybrid HTS Leads
a fixed lead configuration
Ultimate Minimum helium
Break-Away Leads
usage in “standby” mode
APPLICATIONS
• MRI or NMR • Accelerators and Colliders
• Magnetic Energy Storage (SMES) • Conductor Testing & Characterization
• Fusion Energy
HELIUM USAGE
Standard AMI vapor cooled current leads (VCCL) have been shown to evaporate approximately
2.8 x 10
-3 liters/(hour • amp • pair) when operated at the rated design current. These leads are
expected to provide this performance under normal operating conditions. However, a more
conservative value of 3.2 x 10
-3 liters/(hour • amp • pair) is recommended for system design
calculations. Helium consumption at zero current is approximately 60% of rated current consumption.
Consumption rates assume the use of AMI superconducting bus bars and fixed current leads with
soldered connections. These specifications do not apply for breakaway current leads which have a
lower consumption rate in standby mode. The use of water-cooled power cables, resistive cold end
bus bars, improperly sized bus bars, or high contact resistance joints may cause consumption rates to
be higher than those stated above.