GB400202A - Improvements in and relating to electric regulating systems - Google Patents

Abstract

400,202. Automatic regulation. BRITISH THOMSON. HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Garman, G. W. ; 98, Reynolds Street, Scotia, New York, U.S.A.) April 13, 1932, No. 10613. Convention date, April 17, 1931. [Class 38 (iv).] The voltage of an alternating-current circuit 10 is regulated by connecting in the circuit the secondary winding 14 of a booster transformer 11 having a centre-tapped primary winding, the two halves 12, 13 of which are alternately energized through a pair of electric valves 19, 20, the output of which is regulated, in accordance with the voltage of the circuit 10, by controlling the phase relation between the grid and anode potentials by means including a voltage responsive bridge. In the form shown, the grid circuits of the valves are energized through a static phase shifting circuit comprising condensers 24, 25 and a variable impedance 26 connected in series across the circuit 10. One of the condensers 25 is connected to the primary winding of a grid transformer 27 with a divided secondary winding connected to the grids. The impedance 26 is in the form of a transformer, with a secondary winding short-circuited through a pair of valves 43, 44, the conductivity of which varies in response to variations in the voltage of the circuit 10. Such variations upset the balance of the bridge, which comprises pairs of resistances 29, 31, and 30, 32 with dissimilar characteristics, and energize the primary winding of a transformer 40 controlling the grid potentials of valves 36, 37 which are connected in a circuit including a condenser 35 and a transformer 33 connected across the circuit 10. The variations thus produced in the potential of the condenser 35 effect corresponding variations in the conductivities of the valves 43, 44 and hence in the impedance of the transformer 26, thereby advancing or retarding the phase of the grid potentials of the valves 19, 20 to effect the required changes in the voltage supplied to the booster transformer 11. Specifications 399,240 and 400,206 are referred to.