SELECTOR SWITCH FOR TWO AC SUPPLY MAINS Russian patent published in 1997 - IPC

FIELD: selection of asynchronous ac mains incorporating stand-by power supply provision; power systems of automatic-control and computing devices. SUBSTANCE: selector switch has first ac mains bus, second ac mains bus, and thyristor switches connected to buses and having their outputs combined and connected to load. Connected to buses are also electric isolation units whose outputs are connected through zero detectors, voltage monitoring units, and logic processing unit to inputs of matching device whose outputs are connected to control inputs of thyristor switches. Each voltage monitoring unit has series-connected rectifier, parametric regulator, peak detector, and comparator. Comparator second input is connected to output of reference voltage supply. Logic processing unit has inverters whose inputs are connected to unit inputs and to first inputs of NAND gates. Delay elements are connected to outputs of RS flip-flop and to first inputs of AND gates whose outputs function as unit output. EFFECT: improved design. 3 cl, 4 dwg