Intrinsically safe emergency voltage supply - has battery supply switched in over voltage-current regulator and diode preventing reverse flow of mains when emergency supply is active

摘要

An emergency voltage supply for a data transmission system steps in when the main supply fails and it is intrinsically safe in operation. The mains supply (1, 2) is connected over a bridge rectifier (3) to a conductor (4) coupled to output via a diode (5), that prevents reverse flow when the emergency supply is active. A charge regulator (8) maintains the condition of two standby batteries (10, 11). If the main supply falls a relay circuit (13) is switched to cut in the battery supply. The voltage is supplied to an output (6, 7) over an intrinsically safe voltage-current regulator (12).