56 Chapter 7 Parallel System And LBS System
Liebert NXC 30kVA And 40kVA UPS User Manual
Figure 7-1 Schematic of typical parallel system (with common input, separate batteries and output)
7.2.3 Power Cable
The power cable wiring is similar to that of the UPS module. Refer to
3.1 Wiring Of Power Cable
.
The bypass and rectifier input supplies must use the same neutral line input terminal. If the input has a current leakage
protective device, the current leakage protective device must be fitted upstream of the neutral line input terminal
.
Note
The power cables (including the bypass input cables and UPS output cables) of each UPS module should be of the same length
and specifications to facilitate load sharing.
7.2.4 Parallel Cable
Shielded and double-insulated parallel cables available in lengths 5m, 10m and 15m must be interconnected in a ring
configuration between the UPS modules, as shown in Figure 7-2. Method: connect a module parallel cable from its
PARA1 port to the PARA2 port of another module. Follow this method to connect other parallel cables.
The ring connection ensures the reliability of the control of the parallel system. Be sure to verify the reliable cable
connection before starting up the system!
Figure 7-2 Parallel signal cables connection (Parallel system)
Other power supply
Mains input
L1
,
L2
,
L3
,
N
Fuse
Battery 1
Rectifier
Charger
Inverter
Static
switch
Q1
Q5&Q6
Q1EXT
QUPS
L1, L2
,
L3
,
N
To load
Q3
Output distribution
Q1
Q3
L1
,
L2
,
L3
,
N
Q2EXT
QBYP
Battery 2
Q2
Q5&Q6
Q2
External
Inverter
Fuse
Charger
Rectifier
Static
switch
Mains input
L1
,
L2
,
L3
,
N
bypass
switch
E
x
ter
nal
m
ai
nt
enanc
e by
pas
s
UPS 1
UPS 2
UPS 3
UPS 4
LBS 1
PARA 1
LBS 2
PARA 2
LBS 1
LBS 2
PARA 1
PARA 2
LBS 1
LBS 2
PARA 2
LBS 1
LBS 2
PARA 1
PARA 2
PARA 1
Summary of Contents for NXC 30kVA
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