2.5 Major Internal Components and Operating Principle
The UPS is composed the components described in Figure 2.4 on the next page. The Table 2.1 below, describes the operation
of various circuits through the components.
Component Operation/Function
Transient voltage surge suppression (TVSS)
and EMI/RFI Filters
Provide surge protection. Filter electromagnetic interference (EMI) and radio frequency interference
(RFI). Minimize any surges or interference present in the utility line and protect the sensitive equipment
even when on internal bypass power.
Rectifier/Power factor correction (PFC)
circuit
In normal operation, converts utility 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 sine wave
input current ensures efficient use of utility power and reduces distortion reflected on the utility making
cleaner power available to devices that are not protected by the UPS.
Inverter
In normal operation, inverts the DC output of the power factor correction circuit into precise, regulated
sine wave AC power. When utility power fails, the inverter receives energy from the batteries through the
rectifier. In both normal mode and bypass mode, the UPS inverter remains online, generating clean,
precise, and regulated AC output power.
DC to DC charger
When the UPS is connected to utility power and the rectifier is operating, the battery charger regulates
energy output from the rectifier/PFC to continuously recharge the batteries.
Static bypass switch
In the event of an output overload, over temperature condition, or other failure, the switch automatically
transfers connected equipment to bypass power.
Batteries
Up to 3 strings of long life, valve regulated, non-spillable, lead-acid batteries depending on back up run
time requirements. See Specifications on page59, for approximate run times.
NOTE: To maintain battery design life, operate the UPS in an ambient temperature of 68 °F to 77 °F
(20 °C to 25 °C).
Maintenance bypass Breaker electrically isolates the UPS and internal batteries for maintenance.
Table 2.1 Major Component Operation
2 Product Description Proprietary and Confidential ©2023 Vertiv Group Corp. 9
Vertiv™ Liebert® EXS Installer/User Guide
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