GB366097A - Improvements relating to railway signalling apparatus - Google Patents

Abstract

366,097. Railway signals. PETER, L. H. and WESTINGHOUSE BRAKE & SAXBY SIGNAL CO., Ltd., 82, York Road, King's Cross, London. Oct. 29, 1930, No. 32547. [Class 105.] An indicator for a semaphore arm and spectacle signal having its lamp continuously supplied with alternating current is of the direct-current polarized type and is supplied with unidirectional current from the lamp circuit through full- or half-wave rectifiers which may be of the metal compound type described in Specification 194,653, [Class 38 (ii), Electric currents, Converting &c.], Failure of the lamp will deenergize the indicator and may so, or otherwise, give a warning. As shown in Fig. 1, a fullwave rectifier 10 is connected across part of a resistance 7 in series with the signal lamp 3 in the secondary circuit of a supply transformer 5. The output terminals of the rectifier are connected to the indication leads 11, 12 through a contact device 15 which is controlled by the semaphore arm 1 so that the polarized indicator 19 is energized normally or reversely in accordance with the signal setting. Failure of the lamp 3 or any fault in the signal setting is shown by the de-energized indicator showing " signal wrong." A separate indicator for the lamp may be connected to the same or to additional indication leads with a separate rectifier. In the arrangement shown in Fig. 5, a direct-current relay 44 in parallel with a rectifier 45 is inserted in the circuit of the lamp 3 so that on failure of this lamp an auxiliary lamp 41 is lit over back contact 46-48. The indicator 19 is energized normally or reversely, in accordance with the position of the signalcontrolled contact 15, over half-wave rectifiers 27 or 28, only if the main lamp 3 is lit and the relay 44 therefore energized to close its front contact 46-47. In the arrangement shown in Fig. 4 two current transformers 33, 34 in the lamp circuit supply two reversely set full-wave rectifiers 35, 36, one or other of which is connected by the signal-controlled contact 15 with the indication leads 11, 12. The indicator instead of being directly actuated, as described, may be controlled by a direct-current polarized relay which is normally or reversely energized by rectified current in the manner described above.. Where half-wave rectifiers are used they may be arranged as byepass rectifiers.