GB632469A - Improvements in or relating to systems comprising vibratory inverters - Google Patents

Abstract

632,469. Converting. ERICSSON TELEPHONES, Ltd., and MITCHELL, J. H. Nov. 24, 1947, No. 31040. [Class 38 (ii)] An arrangement for obtaining an alternating current comprises a direct current source feeding the primary circuit 1 of a transformer TR through interrupter contacts wherein the circuit is periodically varied to produce an alternating current in a load circuit R connected to the secondary winding 2 of the transformer, the load circuit including at least one winding 4 of each of one or more saturable reactors LC, each of which has a magnetic circuit separate from that of the transformer and which is alternately saturated and desaturated to limit the current at the contacts during the make- and-break thereof. At the same time the alternately poled direct current pulses are fed to a series resonant circuit consisting of an auxiliary winding 3 on the saturable reactors and a capacitor C, the natural frequency of the circuit being such that a half cycle of oscillation is approximately of the same duration as a current pulse from the direct current source, thus ensuring that the reactor is desaturated and therefore that the contacts are carrying minimum current during the make-and-break thereof, so reducing wear. Fig. 2 (not shown) illustrates an embodiment wherein the resonant circuit is connected across the secondary winding of the transformer and Fig. 3 (not shown) has a delay circuit in series with the winding 3 so that the current pulse therein is retarded and serves to de-saturate the core for a current pulse subsequent to that from which it was derived. The Provisional Specification describes an embodiment in which the resonant circuit feeds a full wave rectifier which in turn feeds the saturating winding of the reactor; also saturable reactors may be included to control the power output of the converter.