IV405E Rev.000 SIEL S.p.A.
Data di emissione: 2018-06-22
Pag. 16 di 50 + FR
3.9
UPS parallel Installation
The following sections introduce the installation procedures specified to the parallel system.
3.9.1 Cabinet installation
Connect all the UPS needed to be put into parallel system as below picture.
Make sure each UPS input breaker is
in “
off
” position
and there is no any output from each
UPS connected. Battery groups can be connected separately or in parallel, which means the
system itself provides both separate battery and common battery.
WARNING!
Make sure the N, A (L1), B (L2), C (L3) lines are correct, and
grounding is well connected.
3.9.2 Parallel cable installation
Shielded and double insulated control cables available must be interconnected in a ring
configuration between UPS units as shown below. The ring configuration ensures high
reliability of the control.
3.9.3 Requirement for the parallel system
A group of paralleled UPS behaves as one large UPS system but with the advantage of
presenting higher reliability. In order to assure that all UPS are equally utilized and comply with
relevant wiring rules, please follow the requirements below:
1) All UPS must be of the same rating and be connected to the same bypass source.
2) The outputs of all the UPS must be connected to a common output bus.
3) The length and specification of power cables including the bypass input cables and the UPS
output cables should be the same. This facilitates load sharing when operating in bypass
mode.