GB501412A - Improvements in and relating to regulators for dynamo electric machines - Google Patents

Abstract

501,412. Automatic control systems. BRITISH THOMSON HOUSTON CO., Ltd. Aug. 25, 1937, No. 23343. Convention date, Aug. 28, 1936. [Class 38 (iv)] Electromotive force.-In a regulating system for an alternator 2 which comprises exciting rectifiers 6, 7, the grid potential of which is controlled by auxiliary discharge devices 20, 30 in response to voltage variations on the line 1 supplied by the alternator, additional discharge devices 106, 107, operating on a higher anode voltage, supply increased excitation on the occurrence of transient low voltage conditions. The grid circuits of these devices 106, 107 include a resistance 69 and a fixed potential 28 ; the resistance 69 is supplied with D.C. proportional to the line voltage from the secondary 65 of a transformer 60 so that a fall of line voltage will increase the potential on the grids to render the additional discharge devices operative. The regulation is normally effected by D.C. potentials applied to resistances 43, 77 in the grid circuits of rectifiers 6, 7 by machine current and voltage conditions respectively. The resistance 77 is in parallel with a condenser 10 intermittently charged through the auxiliary discharge device 30, the grid of which is transformer-coupled to the anode circuit of a discharge device 20. The grid circuit of the device 20 includes the D.C. voltages across a constant potential discharge device 25, a resistance 81 supplied with current porportional to field excitation and a resistance 42 supplied with current proportional to the voltage of the line fed by the machine 2.