Inverter; Battery Charger; Dc-To-Dc Converter; Battery - Emerson Liebert GXT4 User Manual

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 21.
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.
1.7

Operating Mode

The UPS operation modes include the following: Mains (AC) Mode, Bypass Mode, Battery Mode,
Battery Recharge Mode, Active ECO Mode and Frequency Converter Mode.
Refer to 3.0 - Operation and Display Panel for details about the operating mode indicators and
control buttons.
1.7.1

Mains Mode

During Mains Mode, the mains provides input power to the Liebert GXT4. The filters, PFC circuit
and inverter process this power to provide high-quality sine wave power to connected loads. The UPS
maintains the batteries in a fully charged state.
11
Product Description
® ™
Liebert GXT4