GB596830A - Improvements in or relating to transformer for variable voltage - Google Patents

Abstract

596,830. Electricity supply. SOC. ANON. DES MANUFACTURES DES GLACES ET PRODUITS CHIMIQUES DE ST.-GOBAIN, CHAUNY, ET CIREY. July 31, 1945, No. 19685. Convention date, April 21, 1944. [Classes 38 (ii) and 38 (iv)] Transformer arrangements.-To provide on load voltage variation of the supply to a load having a varying resistance, such as a mass of glass in a glass furnace, the supply is connected in series with the secondary of a regulating transformer which has a tapped primary, at least three switches being used to connect different tapped sections of the primary to different phases of the supply. Load 6 is supplied from one phase 10, 1 of a three-phase supply through a transformer T, the secondary 2 of which is in series with secondary 3 of regulating transformer T2. The primary of T2 is divided into two parts 4, 5 with three connections, including switches A, B, C to the supply phases 10, 11, 12. By closing any two or all three switches A, B, C manually or by a controller, the phase and magnitude of voltage in secondary 3, and therefore of that, across the load, may be varied without interrupting the current in both primary parts 4, 5 at once. If the supply voltage is suitable, transformer T, may be omitted, secondary 3 being in series with phase 10, 11. Possible values of load voltage in terms of voltage V of secondary 2, and ratio K of the voltage across secondary 3 to V are given, Fig. 2 (not shown), both for the connections as shown in Fig. 1 and with switches A, B connected to lines 11, 10 respectively. In supplying a three-phase load, each main transformer secondary is in series with the secondary of one of three regulating transformers, the primaries of which have three taps, corresponding tap switches being ganged for simultaneous operation.. Fig. 3, 4 (not shown).