Reserve Ac Supply Mode (Single); Maintenance Bypass Mode (Single) - Delta NT-15K User Manual

When the utility AC power fails or unstable voltage occurs, the batteries will instantly
provide DC power to keep continuous operation. Hence, the UPS output will not be
interrupted.

3.3 Reserve AC Supply Mode (Single)

Power Flow
RESERVE
RECTIFIER INPUT
BREAKER
MAINS
Figure 3-3: Reserve AC Power Supply Mode Block Diagram_ Single Unit
When the inverter encounters abnormal situations such as over temperature, long-
time overload, output short circuit, abnormal output voltage and exhausted battery,
the inverter will automatically shut down itself for self-protection. Meanwhile, if the
reserve AC power is normal, the static switch will switch to the reserve AC power
to supply power to the loads without any interruption of power supply. After the
abnormal situations mentioned above are eliminated, the static switch will switch
back to the main AC source (see Figure 3-3).

3.4 Maintenance Bypass Mode (Single)

Power Flow
RESERVE
RECTIFIER INPUT
BREAKER
MAINS
Figure 3-4: Maintenance Bypass Mode Block Diagram_ Single Unit
MANUAL BYPASS
BREAKER
Power Flow
RESERVE INPUT
BREAKER
RECTIFIER INVERTER
BATTERY BANK
Power Flow
MANUAL BYPASS
BREAKER
RESERVE INPUT
BREAKER
RECTIFIER INVERTER
BATTERY BANK
Chapter 3
STATIC SWITCH
STATIC SWITCH
6
Operation Modes
Power Flow
Power Flow
LOAD
OUTPUT
BREAKER
Power Flow
LOAD
OUTPUT
BREAKER