GE Industrial Solutions SG Series 10 – 20 – 30 – 40 kVA Installation Guide - Manual (Page 36)

3.9 RPA PARALLEL SYSTEM CONNECTION
WARNING !
This operation must be performed by trained personnel before the initial start-up.
ENSURE THAT THE UPS INSTALLATION IS COMPLETELY POWERED DOWN.
3.9.1 Power wiring of parallel units
To guarantee good Load sharing between the units of a parallel system, we recommend that the cable
length from the input distribution board (5) to the output distribution board (10) is equal for each unit
(a+b = c+d = e+f = g+h = i+l = m+n = o+p = q+r).
Tolerance: +/-10%.
The AC input power of the Bypass must be the same for all units of the parallel system - no phase shift
allowed between units.
NOTE !
It is strongly recommended that no transformers, automatic circuit breakers or fuses
should be inserted between the unit’s output and the Load common bus bars.
However, it is recommended that a disconnection or isolation switch is installed in
order to totally isolate a unit if needed.
1 = Rectifier
2 = Inverter
3 = Automatic Bypass
4 = Manual Bypass
5 = Input Utility Distribution
6 = Unit Output Load
External Battery fuse or
MCB
7 =
8 = External Battery
Common bus-bar and
Output Load Distribution
9 =
= UPS Number 1
2 = UPS Number 2
3 = UPS Number 3
4 = UPS Number 4
5 = UPS Number 5
6 = UPS Number 6
7 = UPS Number 7
Fig. 3.9.1-1 Power wiring of RPA Parallel System
8 = UPS Number 8
Modifications reserved Page 36/45
OPM_SGS_ISG_10K_40K_0US_V040.doc Installation Guide SG Series 10 –20 – 30 - 40 kVA