G-Tec LibraPro, User Manual

Page: 39 / 57

0MNLIBRAPROK10NPENUA 01 Pag. 39 / 57
SW
O
U
T
ex
t
aux
OUT (C)
MAINS (M)
a2
c3
IN (B) IN (B)
OUT (C)
a1 a3
UPS 2
c1
UPS 3
IN (B)
UPS 1
(D)
OUT (C)
c2
(A)
ext
SWOUT
ext
SWO UT
(A) (A)
(A)
4.3 Mains, load and battery connections
Mains, load and battery connections.
All the information contained in the section “Mains, load and battery connections” (page 15) in relation to the UPS
remains valid with the addition of the information set out below.
4.3.1 UPS AC input / output power connection
Refer to the INSTALLATION DRAWINGS manual for information on how to select the cable sections for each
UPS .
Observe the phase connections
Phase L1 of the system must be connected to input phase L1 on all the UPSs; all the output phases L1 must
be connected together and with phase L1 of the load. The connections must be observed for phases L2, L3
and for the input and output neutral.
parallel connect the UPS s as follows:
- Connect the power supply phases L1,L2,L3,N to the
corresponding input phases of each UPS L1,L2,L3,N.
- Connect the load phases L1,L2,L3,N to the corresponding output phases of each UPS L1,L2,L3,N.
The figure shows an example of three units connected in parallel.
Power supply line (M)
UPS input terminal boards (B)
UPS output terminal boards Load (C)
Auxiliary SWOUT ext (A)
a1,a2,a3,c1,c2,c3) length of cables
NOTE: “SWOUT ext” must be provided with an auxiliary contact (open with the switch open and closed with the
switch closed).
Length of the cables
The sum of the lengths of the power supply and output cables must be the same for all units. With
reference to the drawing, these must be: a1+c1 = a2+c2 = a3+c3
a = length of input line cables
b = length of output line cables
The same rule must also be observed with separate power lines: the lengths of the cables of the by-pass
line + output line must be the same between all the UPS connected in parallel.
Lack of compliance with this rule may cause a current imbalance between the UPSs when the load is
powered through the by-pass line.
An overload on the by-pass line of one UPS will lead to a deterioration of the components on that line, both
internal and external to the UPS: that is, the disconnector cables and electronic power components.