American Magnetics 4Q1010PS-430 Integrated Power Supply System - Manual (Page 104)

86 Rev. 5
Operation
Quench Detection
field/current is entered, the Model 430 Programmer automatically begins
ramping at the specified ramp rate.
Point 4. The user presses the RAMP / PAUSE key at a current of 25.15 A
and the PAUSED mode is activated. The Model 430 Programmer
maintains the current in the PAUSED mode.
Point 5. The user presses the RAMP / PAUSE key once again to resume
ramping.
Point 6. The target field/current setting of +40.000 A is achieved and the
Model 430 Programmer switches to HOLDING mode. At this point the
user deactivates the persistent switch heater by pressing the PERSIST.
SWITCH CONTROL key, which removes the magnet from the circuit.
Point 6a. The dashed line between point 6a and 6b is the rapid ramping
down of the power supply current which automatically happens after the
PSwitch Cooled Time has elapsed. Note that the magnet current remains
at the Point 6 value when the magnet was placed in persistent mode.
Point 6c. The user presses the PERSIST. SWITCH CONTROL key which
rapidly ramps the power supply output to the current that is flowing in the
magnet. The power supply matches the magnet current at point 6d.
Point 7. The user again increases the ramp rate and presses the RAMP TO
ZERO key to begin ramping to zero current. The Model 430 Programmer
automatically ramps the current to 0 A.
Point 8. The Model 430 Programmer switches to ZERO CURRENT mode
at 0 A current when achieved and holds at this current until further
commands are issued by the user.
3.15 Quench Detection
The Model 430 Programmer continuously monitors the superconducting
magnet load and can automatically detect a field/current quench condition.
If a quench is detected, the MAGNET QUENCH LED will be illuminated
and the display will appear as shown below. When a quench is detected,
the Model 430 automatically sets the power supply output voltage to zero,
provides a quench output signal (dry contacts) to the rear panel Quench
I/O connector (see page 149 of the Appendix for the connector pinout), and
will not respond to further input until the RESET QUENCH SHIFT-key is