American Magnetics Current Leads for Cryogenic Systems Manual - Manual (Page 9)

Rev. 5, July 2003 Page 9 of 10
B. RECONNECTING THE CURRENT LEADS
WARNING: All AMI current leads are designed to be
connected and disconnected with zero current flow. NEVER
disconnect these leads when any current is flowing in them. Attempting
to do so could result in FATAL ELECTRIC SHOCK.
WARNING: Breakaway leads should be connected and
disconnected only by qualified personnel.
1. Unseal the vapor exhaust on the current leads to ensure proper cooling of the
leads. This will also allow pre-cooling of the current leads.
WARNING: Attempting to reconnect warm breakaway leads
to a superconducting magnet in persistent mode could heat the
magnet and cause a quench. Dangerously high voltages can be
present during a magnet quench that can cause FATAL
ELECTRIC SHOCK.
2. Loosen the fitting on the upper section of the breakaway current lead.
3. Gently push down on the upper section of the breakaway current lead while
slightly rotating it back and forth. You should be able to feel the current lead
female connector engage the lower section male connector. (Do not use excessive
force if the male connector cannot be engaged as ice may be present on the male
connector. Ice can be removed by flowing room temperature helium gas through
the top of the lead down into the cryostat where the male connector is located.)
4. Tighten the brass fitting on the upper section of the breakaway current lead.
5. Reconnect power supply cables to the warm terminals of the breakaway leads.
VI. MAINTENANCE
Generally the vapor cooled current leads are maintenance-free. Periodically check the current
leads to ensure that helium gas vapor is flowing through the leads and they have not become
plugged. The leads are sealed, passive units and repair, other than by factory authorized
personnel, is not recommended.