Off Battery; Figure 58 Load On Ups-Battery Not Available - Liebert 1000kVA Operation & Maintenance Manual

3.3.6

Off Battery

The battery plant can be disconnected from the UPS modules, if required for battery maintenance, by
opening the module battery disconnect (MBD) circuit breaker(s). In this situation the UPS system
will continue to supply conditioned power to the critical load, but if input power fails the UPS system
cannot supply power to the load.
CAUTION
!
When the UPS system is operating with the module battery disconnect (MBD) circuit
breaker(s) open, the critical load is not protected from loss of the utility source power.
For battery maintenance on multi-module systems, Liebert recommends taking the
module requiring maintenance off-line before beginning the work. This precaution will
minimize disturbances on the system bus if input power fails during the maintenance
work.
Figure 58 Load on UPS—battery not available
UPS
CB1
CB2
MBD
Battery
RIB RIB
#3 UPS #2
CB1
R R
I I
CB2
MBD
Battery Battery
RIB
UPS #1
CB1
SBS
R
SBB
I
System
CB2
Controls
Output
SCCT
MBD
(can accommodate up to 6 UPS modules)
79
Operation
BFB
BIB
MBB
SKRU
MIB
To Critical Load
SCCT