8
Chapter 3 Operation Modes
3.6 Back-up Mode (Parallel)
Figure 3-6: Back-up Mode Block Diagram_ Parallel Units
RECTIFIER INPUT
RESERVE
MAINS
BREAKER
RESERVE INPUT
BREAKER
MANUAL BYPASS
BREAKER
OUTPUT
BREAKER
Power Flow
BATTERY BANK
Power Flow
STATIC SWITCH
INVERTER
RECTIFIER
RECTIFIER INPUT
RESERVE
MAINS
BREAKER
RESERVE INPUT
BREAKER
MANUAL BYPASS
BREAKER
OUTPUT
BREAKER
BATTERY BANK
Power Flow
STATIC SWITCH
INVERTER
RECTIFIER
Power Flow
LOAD
UPS 1
UPS 2
Power Flow
Power Flow
Power Flow
When the utility AC power fails or other unstable voltage occurs, the batteries will
instantly provide the inverter with DC power to keep continuous operation. Hence,
the UPS output will not be interrupted (see
Figure 3-6
).