Operation
3.3.5Off Battery
The battery plant can be disconnected from the UPS, if required for battery maintenance, by opening the module battery disconnect (MBD) circuit breaker. In this situation the UPS module will continue to supply conditioned power to the critical load, but if input power fails the UPS system cannot sup- ply 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.
Figure 46 Load on UPS—battery not available
THREE BREAKER MAINTENANCE BYPASS SWITCHBOARD
BFB | MBB |
| Critical |
| Load |
| AC Output |
BIB | MIB |
UPS MODULE
Static
Switch
Disconnects 
Static
Bypass
Switch
Bypass CB
CONTROL POWER
RIB
INPUT |
CB |
MAIN INPUT
SWITCHGEAR
Controls |
Rectifier/ |
Charger |
Inverter |
OUTPUT |
CB |
Battery
MBD
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