UPS user manual
Utilizzo dell’UPS
10
OMD10082 REV. F
3.3 OPERATING
STATUS
The UPS has four different operating modes, as described below:
Normal operation
Bypass operation
Battery operation
Manual bypass
3.3.1 Normal
operation
During normal operation all the circuit breakers/isolators are closed, except for MBCB
(maintenance bypass).
The rectifier is supplied by the AC three-phase input voltage which, on its turn, feeds the
inverter and compensates mains voltage as well as load variations, keeping the DC voltage
constant. At the same time, it keeps the battery charged (floating or boost charge depending on
the battery type). The inverter converts the DC voltage into an AC sine-wave with stabilized
voltage and frequency, and also supplies the load via its static switch SSI.
Picture 2 – Normal operation
3.3.2 Bypass
operation
The load can be switched to bypass either automatically or manually. The manual
changeover is due to the BYPASS SWITCH which forces the load to bypass. In case of failure
of the bypass line, the load is switched back to inverter without interruption.
Picture 3 – Load supplied by bypass
