GAMATRONIC,
A
S
OLAR
E
DGE
D
IVISION
Centric Installation Guide, rel. 4.7
16
3.2.3
Site Preparation
– Electrical
Perform the following procedures before connecting any external cables to
Centric
.
1
.
8 “Circuit breaker selectivity” in this installation guide. That chapter includes
considerations regarding the size of the external circuit breakers on the rectifier input and
bypass input lines.
2.
Verify that circuit breakers on the electrical board that supplies
Centric
are compliant with
local and national codes and Gamatronic system specifications.
3.
Verify that the input and output power cable connections, GND, and neutral lines comply
with local and national codes and are appropriate for the circuit breakers protecting them.
4.
Measure the ac input voltage. Phase-to-phase voltage (measured between L1-L2, L2-L3,
and L3-L1) should be 3x400 Vac ±10 %. Phase-to-neutral voltage (measured at L1, L2, and
L3) should be 230 Vac, ±10 %.
5.
Verify that voltage between neutral and ground is between 0 and +2 Vac.
6.
Check the dc voltage at the switch of the battery cable and verify that it is at least
+385 V and -385 V.
7.
FAST FUSES (SEMICONDUCTOR FUSES) must be used between the battery and the Centric.
For exa
mple, the Bussmann “FWH” fuse.
3.2.4
Cabling
3.2.4.1
NEUTRAL LINE
During both installation and operation of the
Centric
, a neutral line must always be
connected to the UPS. This neutral line must be connected at all times while the UPS is
working and should not be disconnected at any time.
Caution:
If at any time the neutral line becomes disconnected, there will be no input or
output reference voltage because the input neutral line and the output neutral line are
physically linked together. This may result in the system defining its own reference voltage,
which will be set by the load distribution between the three phases.
This may cause
serious damage to the UPS.
.
Caution:
A 4-pole switching system can disconnect the neutral line.
Warning:
If you have a
four-pole
mains-to-generator
switching system, you are in danger
of having the
neutral line disconnected
when the four-pole switch is operated. This can
result in the problems described above.
To avoid these problems, we strongly recommend that if you use a four-pole mains-to-
generator switching system, you install an isolation transformer that constantly provides a
neutral line to the UPS.
