APC 20 - 200 KVA Different types of MGE Galaxy PW systems, Isolation and protection devices

Introduction (cont.)

Different types of MGE™ Galaxy™ PW systems

A	B
1
	D
	C
2

Fig. 2

Single-UPS unit

A	B
1
	D

Fig. 3

Frequency converter without battery backup power

Parallel UPS system

A	B
1
2	D
	C
A	B
1
2	D
	C

Fig. 5

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

Frequency converter with battery backup power

A	B
1	2

Fig. 4

1
Q4S 2
		Galaxy 1
	1
	2	Galaxy 2
1
2		Galaxy 3
1
2		Galaxy 4

Q3BP

Q5N

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.

Fig. 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.

E-51028230XT/BG - 7