GB547315A - Emergency power supply circuit employing electrical discharge tube converters - Google Patents

Abstract

547,315. Electricity supply. STANDARD TELEPHONES & CABLES, Ltd. Aug. 8, 1941, No. 10079. Convention date, Aug. 14, 1940. [Classes 38 (ii) and 38 (iv)] Substituting sources in service.- When the A.C. supply to an A.C. load circuit fails a device CC, responsive,to the supply voltage causes the release of a relay T whereby a relay TR disconnects the supply circuit and reverses the connections between a battery B and valve apparatus V 1 , V 2 connected to the load circuit and normally charging the battery B, and whereby a relay GR disables a regulating circuit associated with the grids of the valves and connects a vibrator E to the grid circuit so that inverter operation at supply circuit frequency is obtained. The regulating circuit comprises a large proportion of the voltage of a potentiometer K across the battery B and the output voltage of rectifiers VR which are energized in accordancewith load circuit voltage. When a time delay switch TD has closed and the valves V 1 , V 2 have reached operating temperature their grid potentials are therefore automatically controlled to maintain constant voltage on a D.C. load circuit (not shown) connected across the battery and to maintain a trickle charge. Should the D.C. load increase considerably non-linear resistances V3 cause a relay OL to operate to introduce current regulation by reducing the proportion of battery voltage in the grid circuits ; the resistances V3 are also in the grid circuit and assist in the current regulation. The capacity of the commutating condensers C 1 , C 2 is such as to give the plate circuits of the valves such a power factor as will cause the transformer Tl to deliver the appropriate output voltage.