Liebert GXTTM User Manual page 5

RECTIFIER/POWER FACTOR CORRECTION (PFC) CIRCUIT
In normal operation, the rectifier/power factor correction (PFC) circuit converts
mains AC 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: the mains power
is used as efficiently as possible by the UPS, and the amount of distortion
reflected on the mains is reduced. This results in cleaner power being available
to other devices in the building not being protected by the UPStation GXT.
INVERTER
In normal operation, the inverter utilises the DC output of the power factor
correction circuit and "inverts" it into precise, regulated sinewave AC power.
Upon a mains power failure, the inverter receives its required energy from the
battery through the rectifier / PFC. In both modes of the operation, the UPS
inverter is on-line and continuously generating clean, precise, regulated AC
output power.
BATTERY CHARGER
The battery charger utilises energy from the Rectifier / PFC and precisely
regulates it to continuously "float" charge the battery system. The battery system
charges whenever the UPStation GXT is connected to mains power.
BATTERY
The UPStation GXT employs valve regulated, non-spillable, lead acid batteries.
At typical room temperatures and with the UPS float charging, the battery system
will last many years. Optional external battery cabinets are available to provide
extended run times.
STATIC BYPASS
The UPStation GXT provides an alternate path for mains power to the connected
load, in the unlikely event of a UPS malfunction. Should the UPS have an
overload, over temperature, or UPS failure condition, the UPS automatically
transfers the connected load to BYPASS providing the bypass voltage is within
specification. BYPASS operation is indicated by an alarm and an illuminated
BYPASS LED (other LED's may be illuminated to indicate the diagnosed
problem). To manually transfer the connected load from the inverter to BYPASS
power, press the output OFF button once.
NOTE: The BYPASS power path does NOT protect the connected equipment
from disturbances on the mains supply and its range of operation is limited to +/-
15% of the nominal input supply voltage.
AUTO RE-START
Upon restoration of the mains AC power after a mains power outage and
complete battery discharge, the UPS will automatically restart and supply power
to the critical load and the battery charger automatically recharges the battery.
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