Liebert PowerSure PSI 1000 - 3000VA 60 Hz 120V - Manual (Page 23)

Modes of Operation
17
7.0 M
ODES OF
O
PERATION
7.1 Normal Mode
During Normal mode operation, the PowerSure PSI supplies conditioned, computer-grade power to
the connected equipment: utility power passes through the TVSS circuitry and the EMI/RFI filters
and then through the Inverter (1000VA & 1440VA) / Bi-Directional Converter (1920VA, 2200VA and
3000VA) to connected equipment.
When the UPS is in Normal mode, the AC Input Indicator illuminates green. The UPS display in
Figure 14 shows the UPS operating in Normal mode with 26% - 50% load connected to the output.
Figure 14 Normal mode operation with 26-50% load
The PowerSure PSI continuously monitors the batteries to maintain them in a fully charged state.
The battery charger operates whenever AC power is present, even if the UPS is switched Off. By
default, the UPS is set to perform an automatic battery test after it has been operating continuously
for two (2) weeks. The automatic battery test can be disabled via MultiLink.
7.2 Buck/Boost Mode
The Automatic Voltage Regulator (AVR) circuitry compensates for fluctuations in utility power, such
as voltage surges and sags. When the PowerSure PSI detects an abnormality, it raises the undervolt-
age (boost) or lowers the overvoltage (buck) as needed. The AVR operates automatically and main-
tains the output voltage to the connected critical equipment, without utilizing the batteries.
The Buck/Boost Indicator flashes green when the UPS is operating in Buck mode and illuminates
green when the UPS is operating in Boost mode (see Troubleshooting section for details).
Figure 15 Buck/Boost mode operation with 51-75% load and 21-40% battery capacity
Utility power present ...
... and within operational limits
Indicator shows
UPS in Boost Mode
(solid green)