MGE UPS Systems user manual System description, Schematic diagram of the Galaxy PW system

Galaxy PWTM 100 to 225 kVA

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

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.

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).

Schematic diagram of the Galaxy PW™ system

		rectifier/	inverter (B):
		charger (A):	DC to AC
		AC to DC	power	isolation and
		power
				protection:
(1)	*FUSE			Q5N
				*FUSE
normal				load
AC input	Q1
	isolation
	and		QF1: isolation
	protection	harmonic
		fliter	and protection
			battery (D):
			backup power
		isolation:
		Q4S	static bypass (C):
(2)
bypass
AC input
		maintenance bypass:
		Q3BP

Fig. 1 *The Fuse is to protect against catastrophic rectifier/inverter semiconductor failure.

4 Introduction