DC power supply with two rectifiers and two thyristor switches - permitting no-break switching between battery and AC mains supply

The dc power supply has two rectifiers (1,2) connected to an ac supply network (8). One output (A) of each rectifier is connected to a first load line (7). The second outputs (B) of the two rectifiers are connected to two electronic switches (4,5) (e.g. thyristors) that switch either one or the other second output through to a second load line (6). A battery (3) is connected between the first output of one rectifier and the second output of the other rectifier. When the ac supply is present, both rectifiers are operating, the second switch (5) is closed, the first (4) open and the battery is charged. When the ac supply fails, the dc load is supplied without a break from the battery via the second switch (5). When the ac supply returns only the first rectifier (1) supplies the load (the second switch (5) opens) and the second rectifier (2) charges the battery.