System Application Guide
SAG581126000
Spec. No. 581126000 (Model 700
NVBA
)
Issue AD, November 23, 2009
Page 21 of 123
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Controls a Low Voltage Battery Disconnect (LVBD) contactor located in an associated
Battery Stand.
The LVD circuit card provides three separate control circuits. Each control circuit can be programmed,
through the MCA, with its own disconnect voltage setpoint and one global reconnect setpoint. One LVD
circuit card can control up to four (4) contactors. Any contactor can be controlled by any of the three
control circuits on the card by setting of user-selectable switches.
Where more than one Distribution Cabinet contains an LVD control circuit card, the control circuits on all
LVD circuit cards can be set to any of the three MCA-controlled disconnect setpoints independently with
user-selectable switches.
Each of the three control circuits on any LVD card consists of two individual battery voltage monitors, both
of which must sense low system voltage before disconnection can occur. This redundancy prevents a
control circuit failure from unnecessarily disconnecting loads or batteries.
The user can set the low voltage disconnect circuits for either automatic or manual reconnect.
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Automatic Reconnect:
When system bus voltage recovers to a preset adjustable value, the low
voltage disconnect circuits automatically reconnect the loads (or battery) to the system bus.
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Manual Reconnect:
When system bus voltage has recovered to a preset adjustable value, the user
must issue a command via the MCA to reconnect loads (or battery) to the system bus.
A local switch provided in each Distribution Cabinet can be set to inhibit LVD operation for adjustment,
maintenance, and repair purposes. A local indicator illuminates when the low voltage disconnect circuit has
been inhibited. LVD operation is not inhibited in any other Distribution Cabinets in the power system.
Restrictions
Not available for
bays (no inter-bay busbar landings available).
Cannot be ordered with
if it is to be used with a
Ordering Notes
1) Order one (1) Distribution Bus Panel for each List 21 per '
2) Order fuses and/or circuit breakers, as required, per '
' under ACCESSORY
DESCRIPTIONS.
3) Order input and load distribution lugs, as required, per '
' under ACCESSORY
DESCRIPTIONS.
List 22: Two-Row Distribution Cabinet
Features
♦
Accepts up to two (2) Distribution Bus Panels.
♦
Rated for up to 1000 amperes of distribution.
♦
Available for use in
bays.
♦
See also the description of the Quad Shunt circuit card under List
features.
♦
See also the description of the Low Voltage Disconnect circuit card under
List
features.
Restrictions
Not available for
bays (no inter-bay busbar landings available).
