Fire alarm housing including fault detection circuit - operates with printed circuit card for each function mounted on master card

摘要

The fire alarm housing, including a fault detection circuit, has a battery which can supply a number of alarm bells, spaced around the protected building etc. The battery is associated with a battery charger supplied from the mains. The fault detection circuit, the alarm circuit and a supply control circuit are carried by respective printed circuit cards mounted on a master card. The housing also includes a transformer and the main relays with fuse elements protecting the primary and secondary transformer windings, the current supply for te master card and the alarm bell circuits.