Apparatus for controlling railway signals of the electric light type, whereby the 'danger' indication is extinguished when the 'clear' indication is illuminated, without breaking the circuit to the lamp giving the 'danger' indication

摘要

199,150. Dell, R. March 18, 1922. Lamp signals.-Lamps indicating two or three different signals are energized by alternating or pulsating currents and are operated, without interrupting the circuits through which the lamps are supplied, by the use of a transformer in which the distribution of the magnetic flux within the core is variedi to energize one or other of the lamps. Fig. 1 shows two lamps N, K each in series with two coils wound on the limbs A, C of the transformer. The limb B carries a continuously energized winding D which produces similar but unequal fluxes in the limbs A, C. The coils H, J have induced .is them opposing equal E.M.F.'s so that the lamp K is not energized. The E.M.F.'s in the coils E, F are added and lamp N is lighted. When coil L is energized the flux in limb A is reversed and that in limb C is increased in magnitude. The coils E, F have induced in them opposing E.M.F.'s and the coils H, J assist one another and the lamp K is lighted. A modification is described for controlling three lamps by arranging the main winding of a second transformer to be energized by the coils H, J of the first transformer. Indicators or repeaters may be controlled by extensions of the coils E, F. The coil M in series with the coil L is used to prevent damage in case of a short-circuit on the leads to the supply mains.