GB462773A - An improved device for the periodic opening or closing of electric circuits - Google Patents

Abstract

462,773. Electromagnetic interrupters. SIEMENS BROS. & CO., Ltd., and HUMPHRIES, H. E. Feb. 18, 1936, No. 4881. [Class 38 (v)] [Also in Group XXXIX] To effect the periodic opening and closing of an electric circuit or circuits such as the impulsing circuits in automatic telephone systems, a self-restoring electromagnetic relay is employed which has an operating winding connected in series with a control contact across a source of supply and a retarding winding connected in series with a capacity across the operating winding, the control contact being opened as the relay operates and closed as a consequence of the release of the relay. As shown in the Figure, the self-restoring relay Y is provided with two windings (I) and (II), the latter being in series with a capacity comprising condensers CA and CB and a resistance R. When switched into circuit by an external switch x current flows over the make-before-break contact y to the two winding circuits, the charging current through the winding (II) causing this winding to oppose the operation of the winding (I) and delay the effective operation of this winding. On operation of the contacts the winding circuits are broken and a circuit to a controlled line PW completed. In the restoring movement, the condensers discharge through the two windings in series in such directions that the two windings assist each other in maintaining the flux already existent and thus retard the restoring movement. The retardation effect may be increased by connecting additional condensers between linked points TA, TB or may be varied by variation of the value of the resistance R.