Major Components; Figure 6 Operating Principle Diagram - Emerson Liebert GXT3 Series User Manual

1.4

Major Components

The operating principle of the UPS is illustrated in Figure 6.
Figure 6 Operating principle diagram
Input
TVSS & EMI/
L1
RFI Filters
L2/N
G
The UPS is composed of utility input, TVSS and EMI/RFI filters, rectifier/PFC, inverter, battery char-
ger, DC-to-DC converter, battery, dynamic bypass and UPS output.
Transient Voltage Surge Suppression (TVSS) and EMI/RFI Filters
The Liebert GXT3 has surge protection and filters that protect the connected load from power surges,
electromagnetic interference (EMI) and radio frequency interference (RFI). These features can mini-
mize any surges or interference present in the utility power. The filters also prevent surges or inter-
ference generated by the UPS from adversely affecting devices connected on the same branch as the
UPS.
Rectifier/Power Factor Correction (PFC) Circuit
In normal operation, the Liebert GXT3's rectifier/power factor correction (PFC) circuit converts utility
power to regulated DC power for use by the inverter while ensuring that the wave shape of the input
current used by the UPS is near ideal. Extracting this sinewave input current achieves two objectives:
• Efficient power use by the UPS
• Reduced reflected harmonics
This results in cleaner power being available to other devices in the building not being protected by
the Liebert GXT3.
Inverter
In normal operation, the Liebert GXT3's inverter utilizes the DC output of the PFC to produce pre-
cise, regulated sine wave AC power. When utility power fails, the inverter receives DC power from the
DC-to-DC Converter. In either operation mode, the UPS inverter is online, continuously generating
clean, precise, regulated AC output power.
Rectifier /
PFC
Battery
Charger
8
Dynamic
Bypass
Inverter
DC-to-DC
Converter
Battery
Product Description
Output
L1
L2/N
G