Liebert 700VA, GXT3, 3000VA user manual Operating Mode

Product Description

Rectifier/Power Factor Correction (PFC) Circuit

In normal operation, the Liebert GXT3’s rectifier/power factor correction (PFC) circuit converts mains 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 sine wave 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 that are not protected by the UPS.

Inverter

In normal operation, the Liebert GXT3’s inverter utilizes the DC output of the PFC circuit to produce precise, regulated sine wave AC power. When mains power fails, the inverter receives DC power from the battery through the DC-to DC converter. In either operation mode, the UPS inverter is online, continuously generating clean, precise, regulated AC output power.

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 GXT3 is plugged in, even when the UPS is not turned On.

DC-to-DC Converter

The DC-to-DC converter raises the DC voltage from the battery to the optimum operating voltage for the inverter. This allows the inverter to operate continuously at its optimum efficiency and voltage, increasing reliability.

Battery

The Liebert GXT3 utilizes valve-regulated, nonspillable, lead acid batteries. To maintain battery design life, operate the Liebert GXT3 in an ambient temperature of 0°C to 25°C (32°F to 77°F).

Optional external battery cabinets are available to extend battery run times.

Dynamic Bypass

The Liebert GXT3 provides an alternate path for mains power to the connected loads in the unlikely event of a UPS malfunction. Should the Liebert GXT3 have an overload, overtemperature, or UPS failure condition, the UPS automatically transfers the connected loads to bypass.

NOTE

The bypass power path does not protect the connected loads from disturbances on the mains.

1.5Operating Mode

The UPS operation modes include the following: Mains (AC) Mode, Bypass Mode, Battery Mode, Battery Recharge Mode and Frequency Converter Mode.

For the descriptions of operation mode indicators and control buttons, refer to 3.0 - Operation and Display Panel.

1.5.1Mains (AC) Mode

During Mains (AC) Mode, the mains provides energy to the Liebert GXT3. The filters, PFC circuit and inverter process this power to provide high-level power to connected loads. Meanwhile, the UPS maintains the batteries in a fully charged state.

7 Liebert® GXT3™