IBM R30 Operator's Manual page 129

Battery Backup Unit (Supported)
Note: The battery backup unit (BBU) can only be installed in the rack with a power
distribution unit. The BBU cannot be installed in a rack with a power distribution bus.
In addition to supporting other types of drawers in a rack, the BBU can support only
one CPU-type drawer in a rack.
The battery backup unit contains four 12-volt batteries. It is connected to the power
distribution unit and occupies the area immediately above and behind the PDU, as you look
from the rear.
Note: For a translation of this notice, see the System Unit Safety Information manual.
CAUTION:
The battery backup unit outlets provide 300 V dc. Use these outlets only for devices
that operate at this voltage.
Front View
In Use
Unavailable
Capacity
Exceeded
The front panel of the battery backup unit has three battery status lights to indicate if the
batteries are in use, unavailable, or if their capacity has been exceeded.
If the In Use light is on, the batteries are supplying power to the attached devices.
If the Unavailable light is on, the batteries need recharging or the unit requires service;
contact your service representative.
If the Capacity Exceeded light is on, the batteries cannot provide the power required by the
attached devices.
Rear View
Battery
Status
Lights
Fuse
Battery Status
Safety Cover
Connector
Master CB2
Circuit Breaker
DC Power Outlet
4-7
AC Rack Description