Emerson 480V ユーザーズマニュアル

The Load Bus Synchronizer (LBS) keeps the output of two independent UPS systems or parallel UPS 

systems in synchronization even when the systems are operating in different modes and even when 

either or both systems are operating on batteries. When the LBS is used, one UPS system is desig-

nated as master, the other as slave.
The LBS option is typically used with dual-corded equipment or with either the Liebert Smart-

Switch

™

 or Liebert Static Transfer Switch

™

 (STS) for single-corded equipment.

The LBS operates under the following conditions:

• Both master and slave are on inverter

(either system may be on inverter through the rectifier or on inverter through the batteries)

• Master on inverter and slave on bypass
• Master on bypass and slave on inverter
• Master and slave on bypass IF the bypass source is the same for both systems

For Liebert NX-to-Liebert NX dual bus configuration, only one optional LBS cable is required, the 

built-in LBS will operate normally without an extra LBS control box or interface box. The LBS port is 

X4 on the parallel board (M3). The parallel board is on the interior of the Liebert NX, above and left of 

the power electronics; see Figure 23.
An optional, 9-pin LBS cable is used to connect two UPS systems through each system’s DB9 port on 

its parallel board. For two parallel systems, the LBS cable can be mounted between any two units 

belonging to different parallel systems. For information about the LBS kit or to order the optional 

equipment, see your local Liebert representative.
The LBS cable is connected as illustrated in Figures 13 and 14.

electronics; see Figure 23