APC 20 - 200 KVA User Manual

E-51028230XT/BG

- 7

Different types of
MGE™ Galaxy™ PW
systems

Frequency converter
without battery backup
power

Parallel UPS system

Fig. 2

Single-UPS unit

Fig. 3

Frequency converter with
battery backup power

Fig. 4

See figure 5 showing two parallel-
connected (redundant) UPS units.
A static bypass (C) does not exist in
parallel-connected frequency-converter

configurations.
When increased power is required (two
to four parallel units), an external
bypass must be added (see figure 6).

Isolation and protection
devices

(See figure 1 on previous page):

◗

Q1 (switch):

◗◗

isolation of the rectifier/charger (A)

from the normal AC source (1);

◗◗

rectifier/charger (A) start-up;

◗

QF1 (circuit breaker):

◗◗

battery (D) protection and isolation;

◗

Q5N (switch):

◗◗

isolation of the UPS (B) from the

load;

◗

Q4S (switch):

◗

isolation of the static bypass (C) from

the bypass AC source (2);

◗

Q3BP (switch):

◗◗

bypass switch for maintenance;

◗

FUE (fuses):

◗◗

protection of the rectifier/charger (A)

from the normal AC source;

◗

FUS (fuses):

◗◗

protection of the inverter (B) from the

load.

Note:

◗

switch Q3BP does not exist on

parallel UPS systems constituted to
increase available power;

◗

the "Q3BP" and "Q4S" switches do

not exist on frequency converters;

◗

circuit breaker QF1 does not exist on

installations without batteries.

External bypass for parallel
UPSs and the hot-swap
option

See figure 6.

◗

Q5N (switch): isolation of the

inverters of all the parallel UPS
systems from the load;

◗

Q4S (switch): isolation of the static

bypasses (C) on each parallel unit
from the bypass AC source (2);

◗

Q3BP (switch): bypass switch for

maintenance.

Fig. 6

Q3BP

Q4S

Galaxy 1

Galaxy 2

Galaxy 3

Galaxy 4

Q5N

Fig. 5

Introduction (cont.)