Electric safety monitoring system - has bistable holding relay whose pick=up winding is in acknowledgement circuit, and release winding in fault signalling circuit

摘要

The system consists of a fault signalling circuit with any number of switches connected in series and operated by the plant faulty functioning or by hand. An acknowledgement circuit is in parallel with it, and has an unlocking switch for starting the supervised plant after a fault. A relay is in the main circuit. When the unlocking switch (3) is closed in operation, the relay (D1) is in the acknowledgement circuit, and the fault signalling circuit and the acknowledgement circuit are linked by a bistable holding relay (D2) with the excitation winding (4) on the permanent magnet side in the acknowledgement circuit, and the other, release winding (5) in the fault signalling circuit.