American Magnetics 420 Power Supply Programmer - Manual (Page 52)

34 Rev. 7
Installation
Power-Up Procedure
10. The system should ramp to 10 amperes in approximately 10
seconds. Verify this is the case.
Note
If an energy absorber unit is connected, the Model 420 may take
significantly longer to ramp the current to 10 A. The Model 420
must first develop a supply output voltage to overcome the forward
voltage drop of a connected energy absorber. During actual magnet
operation, the presence of an energy absorber will not significantly
delay the ramping operation since the Model 420 control gain is
increased by orders of magnitude when an inductive load is
connected.
11. When the programmed current is achieved, the Current/Field Limit
LED adjacent to the 352*5$00(' &855(17),(/' switch will
be illuminated. The display should show “+ 10.00 A
−
” indicating
that the Model 420 is in the holding mode at the programmed
current value.
Note
There may be a discrepancy between the current shown on the power
supply display and the current displayed on the Model 420. The
shunt measurement system incorporated in the Model 420 is
normally more accurate than the power supply shunt. The Model
420 is calibrated to 0.1% of the actual current, which is typically five
times more accurate than most integrated power supply shunts.
12. Verify that the output current display of the power supply indicates
that it is supplying 10 amperes to the load (which is only the
cabling in this case).
13. Set the programmed current to the current limit value. Refer to
paragraph 3.2.2.3 on page 45 to determine the current limit value.
After the new programmed current value is entered, the Model 420
should ramp automatically to the new setting.
14. When the new programmed current value is reached, the power
supply current display should also indicate the new value.
15. Press the 5(6(7=(52 button to ramp the system to zero current
(LED indicator on button should energize).
16. Perform remote control software checkout as required.
17. Turn off the power supply.