Chapter 1 Overview 5
APM 300 Integrated UPS Single Module And Parallel System User Manual
1.3.5
Battery Circuit Breaker (BCB)
The external battery shall be connected to the UPS through the BCB. The BCB box is an option, which shall be
installed near the battery. The BCB is closed manually or electrically. The BCB has undervoltage tripping coil.
Upon the battery undervoltage, the UPS control circuit will send a signal to the coil to trip the BCB. It also has a
magnetic trip facility for overload protection.
1.4
Parallel System
As shown in Figure 1-4, two UPS modules can be parallel-connected to form a parallel system to increase the
system capacity or reliability, or both. The load is equally shared between the paralleled UPSs.
Qin UPS 1
Qin UPS 2
Qout UPS 1
Qout UPS 2
UPS 1 output
UPS 2 output
L1, L2, L3
L1, L2, L3
N
N
Supplied by others
Input mains supply
L1, L2, L3, N
Charger
Rectifier
STS
Inverter
Input mains supply
L1, L2, L3, N
Charger
Rectifier
Inverter
STS
UPS 2 output distribution
unit 0
~
2 pcs
L1, L2, L3, N
L1, L2, L3, N
UPS 1 output distribution
unit 0
~
2 pcs
UPS 1 output distribution
UPS 2 output distribution
Figure 1-4
Parallel system
1.4.1
Parallel System Features
1. The hardware and software of parallel system are completely the same as those of single UPS module. The
parallel configuration is achieved through settings in configuration software. The parameter settings of each
UPS module in parallel system should be the same.
2. Parallel control cables are connected in a ring, providing both system reliability and redundancy. Dual bus
control cables are connected between any two UPS modules of each bus. The intelligent parallel logic provides
the user with maximum flexibility. For example, shutting down or starting up UPS modules in a parallel system
can be done in any sequence. Transfers between normal and bypass modes of operation are synchronized and
self-recoverable, for example, following overloads and their clearance.
3. The total load of the parallel system can be queried from each UPS module's LCD.
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