A reinforced CB trip chain supervision scheme.
One of the traditional applications of the auxiliary relays are in those where the safety and reliability in the operation are key factors, considering its record in reliability, repeatability, a negligible rate of failures (λ in the order 107 or better) and ability in providing isolation. With these characteristics, is not a rarity when we find these devices have colonised the “supervision of critic elements in the trip chain” being the outstanding members of this the coils of the trip circuit itself and also, in a very refined approach, the coil of the trip circuit relay (a redundancy for very critic trip elements).
The reliability in operation is based in the preservation of a key design criterion, where the simplicity and ruggedness are the paradigms. It is clear that those supervision relays are a little bit more sophisticated than those closely related auxiliary relays (and a little bit less complex than those belonging to the third family branch, the timed relays), but either case the rule “simpler is safer and reliable” is kept as a transversal design principle in Arteche.