Ericsson RBS 2106 Hardware Reference Manual page 269

1 Product Overview
The BFU-21 supplies battery back-up system voltage to the RBS and
disconnects the battery when it has reached its lower discharge limit. The
contactor can disconnect and connect the battery with a control signal from
the Supervision Module (SM).
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The BFU has the following functions:
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2 Dimensions
The BFU-21 has the following dimensions:
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267 mm
Supplies priority power to transmission equipment. Power to transmission
equipment can be distributed even if a battery is not present. The relay can
select the power source with a control signal from the SM.
Supplies priority power to the EC output. The EC output is protected from
reverse currents by a diode. Power to the EC output can be distributed
even if a battery is not present. The relay can select the power source with
a control signal from the SM.
Communicates on the EPC bus (opto cable) with the DXU. If the EPC bus
is not present, the BFU operates at its default values. The battery voltage,
current and temperature are monitored and alarms are sent on the EPC
bus.
Disconnects the batteries, if the current is too low or the temperature is too
high. Reconnects the batteries when the temperature returns to normal.
Sends a "Battery temperature sensor fault" message to the DXU when the
battery temperature is faulty.
Disconnects battery back-up manually or by control signals on the EPC
bus.
The SM provides self-detection of internal faults and stores them in non-
volatile memory.
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82 mm
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226 mm 5 kg
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EN/LZT 720 0234 R1A