Lucent Technologies Lineage
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2000 ECS-12 Controller J85501D-2
2 - 6 Product Description
Issue 3 August 1998
to indicate the onset of battery discharge to allow enough time
for maintenance personnel to respond before battery reserve is
exhausted. When a BD alarm occurs, service is not usually
affected immediately. However, since attention is required in a
limited time, BD is considered a Major alarm, and all three
Power Major alarm groups are issued to the office alarm system
when a BD occurs.
It should be noted here that a BD alarm does not necessarily
indicate that rectifier output current has been lost or reduced. A
BD alarm can be caused by misadjusted rectifier output voltage
during otherwise normal operation. It can also be caused by
current overload on normally functioning rectifiers.
The voltage threshold for the BD alarm is selected by the user by
setting a group of DIP switches on the 113B. The setpoint is
typically at least 1 volt below the plant float voltage for nominal
48V plants or 0.5 volts below the float voltage in 24V systems.
This threshold avoids nuisance alarms due to component
tolerances, variations in load, and other transient conditions.
The actual BD threshold settings that may be selected are listed
on Figure 4-3 and on a label on the controller itself. The range of
available settings is based on the most common battery float
voltages for 24V and 48V systems.
Selective High
Voltage
Shutdown
The controller is equipped to detect a high voltage condition on
the plant bus. Such a high voltage condition is typically caused
by lightning-induced transients on the commercial ac power
lines. A rectifier failure might, however, cause an individual
rectifier to increase its output voltage. To prevent high voltage
from damaging the connected telecommunications load, the
controller will shut down rectifiers that deliver high voltage
power.
When the controller detects an increase in the plant voltage
above a preset threshold, it immediately issues an HV alarm to
the external alarm system. HV is considered a Major alarm, so
all Power Major alarm groups are also issued.
When reporting the alarm, the controller sends a simultaneous
shutdown signal to all rectifiers. Since the outputs of all rectifiers
are paralleled in the plant, their output voltages are forced to be
the same. Their output currents, however, may vary widely. In a
high voltage condition caused by an individual rectifier failure,
