Environmental Control Unit; Rectifier System; Cable-Connecting Compartment - Nortel DMS-100 Series Maintenance Manual

The OPM batteries have a maximum of eight strings of Yuasa batteries or six
strings of Eagle Picher batteries. Each battery string consists of 24 cells. The
battery strings connect to the OPM load or the charge bus through the two
BCCs and the BCU.
Note: For major retrofits of Yuasa batteries, Northern Telecom
recommends you convert to Eagle-Picher batteries because of the extended
life expectancy of these batteries.
The batteries are against the back wall of the cabinet. The location of the
battery strings and other back wall components appears in the figure "OPM
bay frame and equipment arrangement OPM-640 (NT8X01AA,AB)".

Environmental control unit

An ECU is at the bottom of each bay. An ECU consists of four circulation
fans, an air damper, an air heater and an air filter. These components interact
to maintain temperature and relative humidity of the OPM cabinet in
acceptable limits for the electronic equipment of the OPM. The OPM has
temperature sensors to detect extremely high or low temperatures.
Rectifier system
The rectifiers convert the commercial ac power supply to dc power to operate
the OPM equipment and fans. The dc power charges the batteries. The
rectifiers are on both sides of the power control unit. The power control unit
consists of an ac service receptacle with surge protection, circuit breakers, and
a switch for manual control of the power source.

Cable-connecting compartment

The cable-connecting compartment is in the end-access compartment. The
cable-connecting compartment provides outside plant cable protection,
terminals, and cross-connections for incoming lines and cables. Refer to
"End-access compartment" in this document.
DMS-100 Family OPM Maintenance Manual XPM14 and up
OPM hardware 5-7