GB638505A - Improvements in or relating to regulators for electric power supply systems - Google Patents

Abstract

638,505. Rectifiers ; automatic control systems for voltage ; automatic regulation. STANDARD TELEPHONES & CABLES, Ltd. May 15, 1947, No. 13100. [Classes 38 (ii) and 38 (iv)] In a voltage regulating system for supplying a load from an A.C. supply, a saturable reactor, in series with supply and load, has control windings D.C. excited from the supply and the load terminals. As shown, the D.C. load terminals 3, 4 are supplied from the A.C. source 1, 2 through the transformer 5 and rectifier bridge 6. The A.C. winding 7, of the saturable reactor 8, is in series with the primary 5a of the transformer 5, the control winding 15 is energized through the rectifier 17 from the source, the control winding 14 is energized from the load terminals while control winding 9 carries a fraction of the output current determined by the value of resistor 11 of regulator 10. A rise of D.C. output current lowers the reactance of 8, a higher voltage is applied to winding 5a which compensates for the increased voltage drop in rectifier 6 due to the rise of load current. A rise in the voltage at the output terminals 3, 4 is supplied to coil 12 and lowers resistor 11, the current through 9 falls and the voltage at 5a is reduced to correct the D.C. output of 6. The fluxes due to coils 14, 15 are opposed and are balanced at the maximum value of supply voltage, a fall in the latter causes a resultant flux which lowers the impedance of 8 and hence raises the voltage at 5a. In a second embodiment, not shown, an A.C. load is supplied through a transformer from an A.C. source. The two control windings of a saturable reactor, which is in series with the transformer primary, are separately energized through rectifiers, from the source and load terminals and are mutually opposed so that their fluxes balance when the supply voltage is a maximum. A fall in supply voltage is therefore accompanied by a lowering of the reactor impedance with a consequent rise of voltage at the transformer primary. Final adjustment to the output voltage is effected by a resistance regulator which is in series with the control coil associated with the supply and which is actuated by the load voltage. Specifications 599,018 and 613,866 are referred to.