MGE UPS Systems Galaxy PW - Manual (Page 12)

4
system description
(see figure 1)
■ a rectifier/charger module (A) converts
3-phase AC power from the normal AC
source supply (1) into DC power for the
normal inverter input and float charges or
recharges the battery;
■ a battery unit (D) provides backup
power for the inverter in the event of a
voltage drop or a normal AC source fail-
ure;
■ an inverter module (B) converts the DC
power supplied by the rectifier/charger
module or the battery unit into 3-phase AC
power for the load;
■ a static bypass module (C) ensures the
instantaneous transfer of the load to the
bypass AC source input in the event of an
inverter shutdown (initiated by the user or
by a protective device) or a sudden over-
load;
■ a maintenance bypass isolates the UPS
for maintenance and transfers the load to
bypass AC source input without interrupt-
ing the supply of power. The maintenance
bypass is made up of three manual
switches (Q3BP, Q4S and Q5N).
Note
■ the normal AC input and the bypass AC
input have different functions and,
depending on the installation, may be pro-
tected differently upstream and/or come
from different sources.
■ when increased power is required, sev-
eral Galaxy PW™ units may be connect-
ed in parallel (up to four). In this configura-
tion, an "isolation" function is added for
the UPS system as a whole for mainte-
nance purposes, without interrupting the
supply of power to the load.
The system may also include:
■ Isolation or auto transformers on both
input and output.
■ 2 CB or 3 CB maintenance bypass
■ different remote control, indication and
display systems.
Introduction
Fig. 1 *The Fuse is to protect against catastrophic rectifier/inverter
semiconductor failure.
Schematic diagram of the Galaxy PW™ system
maintenance bypass:
Q3BP
inverter (B):
DC to AC
power
isolation:
Q4S
isolation and
protection:
Q5N
rectifier/
charger (A):
AC to DC
power
QF1: isolation
and protection
normal
AC input load
battery (D):
backup power
static bypass (C):
bypass
AC input
Q1
isolation
and
protection
(1)
(2)
harmonic
fliter
*FUSE *FUSE
Galaxy PW TM 100 to 225 kVA