GB275784A - Electric regulators - Google Patents

Abstract

275,784. Beatty, W. E., (Bell Telephone Laboratories, Inc.). Aug. 3, 1926. Regulation, automatic.-The voltage of a generator 3 is kept constant by two thermionic valves 6, 7, the first of which is run at saturation. Upon increase of voltage, the filament of the first valve gets brighter causing a larger anode current and therefore, a bigger P.D across an anode resistance 11. The potential of the grid of the second valve is thereby lowered, causing a smaller current to flow in its anode circuit which includes an auxiliary field 5 and thereby reduces the voltage of the generator. By connecting the field 5 to a tapping on a resistance 9 in series with the filament of the first valve, a decrease in field current causes an increase in brightness of the filament, thus giving a cumulative regulating effect. By adjusting the position of the tapping, over, flat, or under regulation can be obtained. Transient voltage variations are corrected by a transformer 17, the primary of which is connected across the mains and the secondary is included in the grid circuit of the second valve. Modifications are described in which the anode battery 10 and cathode battery 16 are replaced by a source of AC, rectified where necessary. In one modification the transformer 17 is replaced by a condenser shunted across the portion 9<a> of the resistance. The device can also be applied to AC generators.