Emerson Liebert GXT4-10000RT208, User Manual

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Product Description
13 Liebert
®
GXT4
™
User Manual
1.6.2 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 waveshape 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.
• 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
Liebert GXT4.
1.6.3 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 mains power failure, the inverter receives its required
energy from the battery through the DC-to-DC converter. In both modes of operation, the UPS inverter is
on-line and continuously generating clean, precise, regulated AC output power.
1.6.4 Battery Charger
The battery charger utilizes energy from the mains power and precisely regulates it to continuously float
charge the batteries. The batteries are being charged whenever the Liebert GXT4 is connected to mains
power.
1.6.5 DC-to-DC Converter
The DC-to-DC converter utilizes energy from the battery system and raises the DC voltage to the optimum
operating voltage for the inverter. This allows the inverter to operate continuously at its optimum efficiency
and voltage, thus increasing reliability.
1.6.6 Battery
The Liebert GXT4 utilizes valve-regulated, nonspillable, lead acid batteries. To maintain battery design life,
operate the UPS in an ambient temperature of 15°C to 25°C (59°F to 77°F). Optional external battery
cabinets are available to extend battery run times. For run times, see
Table 8-8 .
1.6.7 Internal Bypass
The Liebert GXT4 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, overtemperature or any other UPS failure
condition, the UPS automatically transfers the connected load to bypass. Bypass operation is indicated by
an audible alarm and illuminated amber Bypass LED (other LEDs may be illuminated to indicate the
diagnosed problem). To manually transfer the connected load from the inverter to bypass, press the
Standby/Manual Bypass button once and hold it for about 2 seconds
1.6.8 Maintenance Bypass
The Liebert GXT4 provides a manual maintenance bypass in a removable section of the rear of the UPS.
This allows replacement of the UPS in the event of a UPS malfunction while keeping the connected
equipment powered with utility power.
NOTE
The bypass power path does NOT protect the connected equipment from disturbances in
the mains supply.