GB785894A - Improvements in or relating to electrical circuits of the kind including an electro-magnetic device - Google Patents

Abstract

785,894. Electric selective signalling systems. GENERAL ELECTRIC CO., Ltd., and SMART, N. C. July 3, 1956 [June 13, 1955], No. 16999/55. Class 40 (1). [Also in Group XXXIX] Means responsive to the receipt of impulses causes each impulse to be applied to a capacitance which is thereby charged, the said means acting at the end of each impulse to connect the capacitance in a closed circuit with the operating winding of an electromagnetic device which is thus operated by the discharge of the capacitance, the arrangement being such that the power supplied to the operating winding upon the termination of an impulse is greater than would have been supplied if the impulse had been applied directly to the operating winding. As shown, Fig. 1, relay A responds to an impulse received at line terminals 1 and 2, connecting condenser 5 to be charged by the impulse. At the end of the impulse, relay A releases and condenser 5 discharges through the winding of the driving magnet 7 of an uniselector 8 which is thereby moved on through one step. With the high-resistance winding of relay A and condenser 5 connected across the line terminals 1 and 2, the potential difference produced between the terminals (and hence across the condenser 5) is greater than if the relatively low-resistance winding of the magnet 7 were so connected, and therefore the initial current through the magnet winding is also correspondingly greater. In the modification shown in Fig. 2, relay B is energized during an impulse train but releases at the end of it so that any subsequent impulse (the switch 13 now being off-normal) does not re-energize relay B and the ensuing discharge of condenser 5 is applied to the release magnet 14, enabling switch 13 to go home.