System setup, Installation – American Magnetics AMI Superconducting Magnets User Manual
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Installation
System setup
turn off when a quench occurs in a superconducting magnet. The result is that
these power supplies can drive more than 100 amperes through the quench
protection diodes on the magnet for an extended period of time causing diode
failure. This is especially disastrous if the magnet is welded in a dewar. The
dewar must then be cut apart to get the magnet out and replace the protection
diodes. AMI programmer/power supply systems are very good at detecting
quenches and are designed, in conjuction with an energy absorber, to limit the
magnet voltage to less than 5 volts. If you use another vendor’s power supply
system, AMI cannot assume any liability for the costs associated with cutting
the dewar apart and repairing the magnet if AMI determines that the problem
was caused by the non-AMI power supply system.
2.
Make sure the magnet power supply is de-energized and short the output leads
from the power supply together securely.
Note
If an energy absorber is included in the system, short the output leads of the
energy absorber instead of the power supply.
3.
Check for proper power supply system operation (with the output leads
shorted) by ramping the system up and down and adjusting the system current
limit to the current level corresponding to the magnet rated central field (i.e.
rated current).
Note
Refer to the programmer/power supply manuals for the system test procedure.
System setup
1.
Upon satisfactory completion of the instrumentation and control checks, de-
energize all system components and connect the power leads to the vapor-
cooled current leads.
2.
Energize the system instrumentation.
3.
Verify the liquid helium level in the dewar properly covers the magnet (and
persistent switch). This completes the installation and system setup
procedures.