2.3 Parallel System
Up to four UPS modules can be parallel-connected to form a parallel system to increase the system capacity and reliability.
The load is equally shared between the paralleled UPS modules.
Moreover, two UPS modules or parallel system can comprise a dual bus system. Each parallel system has independent
output. Output synchronization is achieved through the LBS cable or LBS device, thus enabling seamless load transfer
between the two parallel systems or single modules through the STS device.
2.3.1 Parallel System Features
1.
The hardware and software of parallel system are completely the same as those of the single module. The
parallel system configuration is achieved through settings in configuration software.
2.
Parallel cables are connected in a ring, providing both system reliability and redundancy.
3.
The total load of the parallel system can be queried from each UPS module's TOUCH SCREEN.
2.3.2 Parallel System Requirements
A group of paralleled modules behaves as one large UPS with the advantage of presenting higher reliability. To ensure that
all modules are equally utilized and to comply with relevant wiring rules, the following requirements apply:
1.
All UPS modules must be of the same series, and connected to the same bypass source.
2.
The bypass and rectifier input sources must be connected to the same neutral line input terminal.
3.
Any RCD, if installed, must be of an appropriate setting and located upstream of the common neutral line input
terminal. Alternatively, the device must monitor the protective earth current of the system. Refer to Warning:
2 Overview
14
Vertiv™ Liebert® APM Plus User Manual
Summary of Contents for APM 0250kMK16FN02000
Page 1: ...Vertiv Liebert APM Plus User Manual 50 250 kVA UPS...
Page 8: ...vi This page intentionally left blank Vertiv Liebert APM Plus User Manual...
Page 30: ...2 Overview 22 This page intentionally left blank Vertiv Liebert APM Plus User Manual...
Page 97: ...5 Operator Control and Display Panel 89 Vertiv Liebert APM Plus User Manual...
Page 188: ...12 Specifications 180 This page intentionally left blank Vertiv Liebert APM Plus User Manual...