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9-14 Replacing the low-voltage disconnect unit
Procedure 9-4 (continued)
Adjusting the LVD unit
Action
Step
1
2
Set the LVA threshold to –47.0 ± 0.2 V dc
3
4
5
6
7
8
9
Set the LVD alarm threshold to –42.5 ± 0.2 V dc
10
11
12
AccessNode P0904244 Issue 1.0
Action
Set the BYP/NORM switch to the BYP position.
On the dc distribution unit, turn all circuit breakers (CB1–CB4) to the OFF
position.
Connect the digital multimeter, set to read dc volts, to the test jacks on the
faceplate of the LVD unit.
Adjust the TEST ADJ potentiometer clockwise (to increase) or
counterclockwise (to decrease) the voltage to –50.0 V dc.
Slowly turn the TEST ADJ potentiometer counterclockwise and monitor the
digital multimeter and the LV ALM LED to determine the LVA threshold.
If the LVA ALM LED
does not illuminate before reaching –47.0 ± 0.2 V dc
illuminates before reaching –47.0 ± 0.2 V dc
If the LVA ALM LED does not illuminate before reaching –47.0 ± 0.2 V dc, use
the TEST ADJ potentiometer to set the voltage reading to –47.0 V dc.
Slowly turn the LV ADJ potentiometer clockwise until the LVA ALM LED
illuminates. Then go to step 11.
If the LVA ALM LED illuminates before reaching –47.0 ± 0.2 V dc, continue to
turn the TEST ADJ potentiometer counterclockwise until the voltage reading
reaches –47.0 V dc.
Slowly turn the LVA ADJ potentiometer counterclockwise until the LVA ALM
LED extinguishes.
Slowly turn the LV ADJ potentiometer clockwise until the LVA ALM LED
illuminates.
Slowly turn the TEST ADJ potentiometer counterclockwise and monitor the
digital multimeter and the LVD ALM LED to determine the LVD threshold.
If the LVD ALM LED
does not illuminate before reaching –42.5 ± 0.2 V dc
illuminates before reaching –42.5 ± 0.2 V dc
If the LVD ALM LED does not illuminate before reaching –42.5 ± 0.2 V dc, use
the TEST ADJ potentiometer to set the voltage reading to –42.5 V dc.
—continued—
Then go to
step 6
step 8
Then go to
step 12
step 14
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