Vertiv Liebert Load Bus Sync Controller, User Manual

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Vertiv
™
| Liebert
®
Load Bus Sync
™
Controller Installation Manual | 6
2.2 Two UPS Units With Common Bypass Line
When two UPS’s are connected with a common bypass line, the bypass line synchronizes the two
inverters. Synchronization can be lost because of protection upstream of the bypass line. Using
the following solution, the two systems will be always synchronized, even if one of the two bypass
lines is out of tolerance. These units will usually be capable of synchronous operation.
Figure 4 Common bypass line
N.B. fuses should be connected at the beginning of the signal line to avoid fires in case of short
circuit in the wires.
2.3 Liebert® Systems and Electrical Generating Devices
The Liebert
®
Load Bus Sync
™
Controller can be used to provide phase reference to the Liebert
®
NX
™
UPS in installations with alternative power sources, such as diesel generators, see Figure 5 .
NOTE
UPS A and UPS B should be configured with main synchronization source to bypass. Otherwise
the UPS’s won’t be capable of synchronous transfer to bypass.
Power
Source B
UPS B
Power
Source A
UPS A
Source
Line B
Source
Line A
UPS A
L1 -Phase Signal
Neutral
L1 -Phase Signal
Common Bypass
Line
Static Switch
To Load
To Others
Static Switch
UPS
B
To Others
Static Switch
Liebert
®
Load Bus
Sync
™
Controller
Liebert
®
Load Bus
Sync
™
Controller
Slave
Master