GB232664A - Improvements in or relating to electromagnetic relays for use in railway signalling or like systems - Google Patents

Abstract

232,664. Automatic Telephone Manufacturing Co., Ltd., and Hudd, A. E. Jan. 19, 1924. Electrical systems, automatic.-On a track circuit supplied with alternating or pulsating current, a rectifying relay, which is substantially aperiodic is used to rectify current from the same source which supplies the track rails circuit in order to energize a direct current relay at the receiving end. The rectifying relay is preferably of the kind described in Specification 156,353, [Class 38 (v), Electric switches &c.], having mechanical means for adjusting the phase. A polarized direct current relay is used and gives three-position signals by reversal of the phase of the current supplied directly to the relay with regard to that supplied to the track rails. Fig. 4 shows the last-mentioned arrangement. The track rails are supplied from mains 45 through a transformer 46 and condenser 47; the rectifying relay 48 has an aperiodic armature which closes the circuit from transformer 50 to the direct current relay 51 during one-half of each cycle and, according to the setting of a switch (not shown), which controls the current supplied to the transformer 50, a rectified current in one or other direction is supplied to the relay 57 and causes the armature 54 to close contacts 57 or 58 for controlling signals. A shunt resistance 59 is placed across the relay 57 to prevent chattering. The Provisional Specification describes a modified circuit for the relay 51.