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System Description
5
2.0 SYSTEM DESCRIPTION
2.1 Transient Voltage Surge Suppression (TVSS) and EMI/RFI Filters
These UPS components provide surge protection and filter both electromagnetic interference (EMI)
and radio frequency interference (RFI). They minimize any surges or interference present in the util-
ity line and keep the sensitive equipment protected.
2.2 Rectifier/Power Factor Correction (PFC) Circuit
In normal operation, the rectifier/power factor correction (PFC) circuit converts utility AC power to
regulated DC power for use by the inverter while ensuring that the waveshape of the input current
used by the UPS is near ideal. Extracting this sinewave input current achieves two objectives:
• The utility power is used as efficiently as possible by the UPS.
• The amount of distortion reflected on the utility is reduced.
This results in cleaner power being available to other devices in the building not being protected by
the Liebert
®
GXT3
™
.
2.3 Inverter
In normal operation, the inverter utilizes the DC output of the power factor correction circuit and
inverts it into precise, regulated sinewave AC power. Upon a utility power failure, the inverter
receives its required energy from the battery through the DC-to-DC converter. In both modes of oper-
ation, the UPS inverter is on-line and continuously generating clean, precise, regulated AC output
power.
2.4 Battery Charger
The battery charger utilizes energy from the utility power and precisely regulates it to continuously
float charge the batteries. The batteries are being charged whenever the Liebert GXT3 is connected to
utility power.
2.5 DC-to-DC Converter
The DC-to-DC converter utilizes energy from the battery system and raises the DC voltage to the opti-
mum operating voltage for the inverter. This allows the inverter to operate continuously at its opti-
mum efficiency and voltage, thus increasing reliability.
Input
Output
Inverter
Battery
Rectifier/PFC
DC-to-DC
Converter
TVSS &
EMI/RFI
Filters
L1
G G
Static
Bypass
L2
N
L1
L2
N
Battery
Charger