15 quench detection, Operation – American Magnetics 05200PS-430-601 Integrated Power Supply System User Manual

Page 106

Rev. 5

Operation

Quench Detection

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 153 of the Appendix for the connector pinout), and

will not respond to further input until the

RESET QUENCH

SHIFT-key is

used to clear the quench detect condition, or until the quench condition is

cleared by a remote command.

+44.36 A

Quench Detect @ +80.56 A

+0.00 Vs

PSwitch Heater: ON