GB260587A - Improvements in and relating to regulators for electric machines or circuits - Google Patents

Abstract

260,587. British Thomson-Houston Co., Ltd., (Assignees of Mittag, A. H.). Oct. 28, 1925, [Convention date]. Regulation, automatic system and apparatus for. - The output voltage of an alternator is regulated by varying the relation of grid potential to anode potential of a thermionic valve used to rectify current drawn from the alternator and supplied to either the field thereof or to the field of an exciter therefor. The field 3 of the alternator 1 is supplied at starting by an auxiliary machine 24 or battery and thereafter from a transformer 4 through the anodes and cathode of a valve 5 and resistor 19. The grids of the valve are supplied through a transformer 21 from a phase shifter 22 connected to the mains 2. If the voltage on the mains increases, the torque on the device 22 is increased and the rotor thereof turns in opposition to the effect of a weight 23 to increase the phase difference between the potentials of the grids and the anodes of the valve 5 and thus reduce the current through the resistor 19 changes the bias on the grids to increase the current through the valve and thereby prevent the. regulating system from " hunting. " The regulating apparatus may be modified in the following respects. Instead of the valve being controlled by the phase relation between grids and plates, it may be controlled solely by variation in magnitude of grid potential, the phase displacement remaining constant and the grids being supplied from the mains through phase setting devices such as a tapping from an inductance connected between two of the phases or through a condenser. The grid bias resistor 19 can be replaced or supplemented by a biassing battery or auxiliary machine, and further instead of it being traversed by the field current it can be traversed by the anode current of an auxiliary valve, the grid of which is energized according to voltage of the mains 2.