Table of Contents
Advertisement
62
Chapter 7 Parallel System & Dual Bus System
7.4 Installation Of Dual Bus System
7.4.1 Cabinet Installation
As shown in Figure 7-7, a dual bus system consists of two independent UPS systems. Each UPS system may be
a UPS module or a parallel system consisting of two parallel UPS modules. The dual bus system has high
reliability and is suitable for load with multiple input terminals. For single-input load, an STS can be fitted to
feed power to the load.
Main input
The dual bus system uses the LBS cable/adapter to keep the output of the two independent UPS systems (or
parallel systems) in synchronization. One system is designated as the master, the other is designated as the
slave. The operation modes of the parallel system comprise master and/or slave operation in normal or bypass
mode.
Place the UPS modules side by side and interconnect the UPS modules according to the following instructions.
7.4.2 External Protective Device
Refer to 3.1.7 External Protective Device.
7.4.3 Power Cable
The wiring of power cables is similar to that of single module system. The bypass and the main input sources
must be referenced to the same neutral potential, and the input earth leakage monitoring devices, if installed,
must be located upstream of the common neutral sinking point.
7.4.4 LBS Cable
For APM-to-APM dual bus system, connect the optional LBS cables (5m, 10m and 15m selectable) between
the two UPS systems as shown in Figure 7-8 to Figure 7-10. The J3 and J4 ports are provided on the front panel
of the bypass module, as shown in Figure 7-5.
Note
You must use the shortest LBS cable to suit the application and must not coil excess. Meanwhile, separate the LBS cable
from the power cables to prevent electrical inteferences.
Liebert APM 150 Integrated UPS Single Module And Parallel System
Bypass
Main input
Parallel
control
cable
Figure 7-7 Typical dual bus system (with STS and LBS)
Main input
LBS
STS
To load
Bypass
Main input
Parallel
control
cable
User Manual
Advertisement
Table of Contents
