GB558658A - Improvements in or relating to electrical systems, particularly systems for converting direct current into alternating current - Google Patents

Abstract

558,658. Converting. STEVENS, A. H. (Electronic Laboratories, Inc). May 20, 1942, No. 6878. [Class 38 (ii)] In an arrangement whereby D.C from a source 25, 26 is converted into A.C. in a load circuit 16 by means of an intenupter 10 which supplies an intermittent current to the two halves of the centrally-tapped primary of a transformer 11, the intermittent current to each half of the transformer primary proceeds by parallel paths which include the two halves of a centrally tapped balanced inductance such as 43, two contacts such as 19, 21, and a current-diverting impedance such as 37 arranged between the contacts. The arrangement ensures the two or more parallel contacts such as 19, 21 dividing the current equally between them even though one contact should break slightly before the other and yet the resultant inductance of the two halves of the inductance 43 is substantially nil. The impedance 37 may be a resistance, an inductance, or a resistance and inductance in series or parallel and a suitable value for each resistance or inductance is four times the resistance or inductance of the vibratory circuit. In a modification, the vibratory reed 17 moves between four instead of two pairs of contacts ; the additional pairs leading to additional balanced inductances ; and central tappings from all four inductances lead to further balanced inductances connected to the transformer primary.