Reference Manual

Unit Description, BFU-21 and BFU-22
Supervision
Module
Shunt Contactor
TM and EC
supply
TM
50A
EPC bus
(opto)
Battery
200A
P008644B
RBS DC
distribution
Contactor
Figure 114 Block diagram of BFU-22
The BFU consists of the following blocks:
• Contactors
• Circuit breakers
• Shunt
• TM and EC supply
• Supervision module
Contactor
The Contactor is used to disconnect the batteries from the system. The
Supervision Module controls the Contactor.
Circuit Breaker
The Circuit Breaker disconnects the batteries if the current becomes too
high. It can also be manually operated on the front of the BFU to
connect or disconnect the batteries from the DC distribution.
Shunt
The shunt is used to sense the input current. The Supervision Module
senses the value, which is used for control of the BFU.
TM and EC Supply
BFU-21 has two TM outputs for supply of transmission equipment and
one EC output for priority supply of the Control Board in the ACCU.
206 (485)
EN/LZT 720 0008 P2A
2001-11-28
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Preliminary