the bedarfsweisen schaltungsanordnung on or shutdown relay on a limited number of veins

摘要

The signalling system allows a number of railway signalling lamps to be operated, using a limited number of signal lines. Selection is made via relays and circuits responding to voltages of differing amplitude, poliarty or frequency. Each group of signal lamps is associated with a relay in the control centre. Depending on whether the selected lamp is in the first or second group of three, a positive or negative DC potential is applied, via contacts of a repeater relay, to further relays. An AC supply is switched via one of the relay contacts to the primary of a transformer connected to one line pair. The secondary supplies the group of lamps, one of which is connected in circuit via the respective relay contacts.