Nortel DMS-100 Series Maintenance Manual page 109

A third 25 A rectifier module is required to support additional optional
equipment beyond a fully-loaded OPAC. When one module fails, the
modules that remain increase output and continue to share the load.
Battery control unit
Locate the BCU at the top left hand corner of bay 1. The BCU contains two
battery charging controllers (BCC 0 and BCC 1).
The BCU charges, monitors and protects the batteries. The BCU
disconnects the batteries from the system when voltage drops below a preset
or operating company determined level. The operating company sets the
level in accordance with the battery manufacturer specifications.
When commercial or standby ac power is not restored before the BCU
disconnects, the system shuts down.
Rectifier shelf
The NT5C06CA MPR25A rectifier modules provide power to the installed
equipment, electronics, fans and batteries. Voltage adjustment is available
from –44 to –56 V dc. Adjust to deliver the output specified for the system:
–52.5 V dc.
The powering circuit allows replacement of a rectifier that has faults without
the disruption of service. When necessary, you can remove or replace a
rectifier module while the system is in operation. The rectifier shelf and
installed rectifiers appear in the following figure.
Two rectifiers are required. A third rectifier can support optional equipment
beyond a fully-loaded OPAC.
Batteries
A maximum of six strings of Eagle-Picher batteries comprise the OPAC
batteries. Each battery string consists of eight batteries. These battery
strings connect to the OPAC load or charge bus through the two BCCs in the
BCU. BCC 0 and BCC 1 control of the battery strings appears in the
following table.
BCC and battery strings
BCC
0
1
DMS-100 Family OPAC Maintenance Manual XPM12 and up
OPAC maintenance overview 2-15
Battery string
0 1 2
4 5 6