GB827750A - Improvements in or relating to power supply systems - Google Patents

Abstract

827,750. Automatic voltage-control systems. STANDARD TELEPHONES AND CABLES Ltd. Sept. 27, 1956, No. 29500/56. Class 38 (4). Relates to circuits in which an A.C. source feeds a D.C. load through a transformer fed bridge-rectifier, the output voltage being stabilized for changes of load or input voltage. In one embodiment, in series with the primary winding of transformer 4 is the load winding 5 of a transductor 6 and an auxiliary bridge rectifier 7, the D.C. output of which operates the control winding of said transductor. Variation of the input A.C. voltage varies correctively the control current of transductor 6, but response is also achieved to change of output voltage by shunting rectifier 7 with the load winding 13 of a further transductor 14. Control winding 17, supplied by a reference D.C. source and control winding 15, energized by the load voltage, have opposing magnetization, rheostat 16 being adjusted so that magnetization from winding 15 just predominates with the minimum acceptable output voltage, i.e. minimum input voltage and maximum D.C. load. Reduction of load tending to increase the output voltage raises the magnetization of transductor 14 to reduce the impedance of winding 13, thus reducing control current in winding 12 and raising the impedance of winding 5 to oppose any change of output voltage. The reference voltage applied at terminals 18, 19 may be derived from the A.C. source by means of the circuits of Specification 745,796 or 754,325. Alternatively the circuit of Specification 792,654 may be substituted for control winding 17 of transductor 14 to provide directly a reference magnetization from the A.C. source, Fig. 2 (not shown). Specifications 599,018 and 665,335 also are referred to.