The
rectifier
/
battery charger transforms the AC current supplied by the mains
into a DC current suitable for the supply to the inverter, maintains the battery
at the appropriate charging level so that it is always capable of supplying
energy for the required time, and recharges the batteries.
The inverter
transforms the direct current supplied by the rectifier or by the batteries into
a sinusoidal AC supply and supplies the user.
The
battery is a reserve of energy that guarantees that the equipment
continues to be supplied even if the mains supply fails.