American Magnetics 430, Installation, Operation And Maintenance Instructions

Page: 131 / 254

R
EV
9 115
A
MERICAN
M
AGNETICS
, I
NC
. O
PERATION
: P
ERSISTENT
S
WITCH
C
ONTROL
a confirmation that the magnet should be placed in persistent
mode.
50
b. When
ENTER
is pressed, the persistent switch is cooled for the
preset persistent switch cooling time (set by the PSwitch Cooled
Time
51
). The display indicates that the persistent switch is being
cooled and indicates the number of seconds (4 in this example)
remaining in the cooling cycle for timer-based switch transitions, or
optionally
indicates the running variance of the magnet voltage for
magnet voltage-based switch transitions.
NOTE
For the magnet voltage-based switch transitions, a variance value
of zero indicates a cooled switch. Therefore, during the cooldown
the display will show a seemingly random sequence of numbers
that should gradually decrease and eventually decay to a value of
zero. Once the variance remains at zero for at least five seconds,
the switch will be considered cooled.
c. When the cooled time is complete, the green
MAGNET IN
PERSISTENT MODE
LED will illuminate and the power supply will
ramp to zero at the PSw P/S Ramp Rate value
52
.
NOTE
The magnet voltage (Vm) is monitored during the power supply
ramp to zero. For a cooled switch, the magnet voltage should
remain at zero. The following steps d through f apply only if the
magnet voltage does
not remain at zero.
50. Pressing the
ESC
key will terminate the command and return the Model 430 Programmer
to the default screen.
51. Refer to on page 86 for timer-based switch transitions.
52. Refer to on page 87.
+50.00 A - Press ENTER to begin
0.00 Vm Persistent Mode
+50.00 A Mode: Cooling Switch (4)
+0.01 Vm PSwitch Heater: OFF
+42.89 A Mode: Power Supply ramping
0.00 Vm to zero current