4
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Operation
4.1 Operation Modes
The UPS is a double-conversion on-line UPS that may operate in the following alternative
modes
：
◆
Normal mode
The rectifier/charger derives power from the AC Mains and supplies DC power to the inverter
while floating and boosting charge the battery simultaneously. Then, the inverter converts the DC
power to AC and supplies to the load.
◆
Battery mode (Stored Energy Mode)
If the AC mains input power fails, the inverter, which obtains power from the battery, supplies the
critical AC load. There is no power interruption to the critical load. The UPS will automatically return to
Normal Mode when AC recovers.
◆
Bypass mode
If the inverter is out of order, or if overload occurs, the static transfer switch will be activated to
transfer the load from the inverter supply to bypass supply without interruption to the critical load. In
the event that the inverter output is not synchronized with the bypass AC source, the static switch will
perform a transfer of the load from the inverter to the bypass with power interruption to the critical AC
load. This is to avoid paralleling of unsynchronized AC sources. This interruption is programmable
but typically set to be less than an electrical cycle e.g. less than 15ms (50Hz) or less than 13.33ms
(60Hz).
◆
ECO Mode
When the UPS is at AC Mode and the requirement to the load is not critical, the UPS can be set
at ECO mode in order to increase the efficiency of the power supplied. At ECO mode, the UPS
works at Line-interactive mode, so the UPS will transfer to bypass supply. When the AC is out of set
window, the UPS will transfer from bypass to Inverter and supplies power from the battery, and then
the LCD shows all related information on the screen.
◆
Parallel redundancy mode (system expansion)
To achieve a higher capacity and / or increase reliability, the outputs of up to four UPS modules
can be programmed to operate in parallel and the built-in parallel controller in each UPS ensures
automatic load sharing.
◆
LBS (Load Bus Synchronization)
The function of LBS is to keep the output of two independent UPS systems (single unit or multiple unit)
in synchronization even when the two systems are operating on different modes (bypass/inverter) or on
batteries. It is usually used with an STS (Static Transfer Switch) connected to the critical load to achieve Dual
Bus configuration.
◆
Maintenance mode (Manual Bypass)
