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4. Operation
4.1 Operation Modes
The UPS is a double-conversion on-line UPS that can operate in the following modes:
◆
Normal Mode
The rectifier/charger derives power from AC and supplies DC power to the inverter while
providing a float and boost charge to the batteries as required. The inverter converts DC
power to AC to supply to the load.
◆
Battery Mode (Stored Energy Mode)
If the AC input power fails, the inverter, which obtains power from the battery, supplies the
load. The UPS will automatically return to Normal Mode when AC recovers.
◆
Bypass Mode
If there is a fault with the inverter or if an overload occurs, the static transfer switch will be
activated to transfer the load from the inverter to bypass supply without interruption to the
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).
