The invention relates to a multipole electrical circuit breaker with a molded insulating case, enclosing:
an operating mechanism having a toggle device coupled to a switching bar common to a plurality of juxtaposed poles inside the case with interposed insulating separation walls,
a trip release cooperating with the mechanism in the event of a fault to bring about breaking of the circuit breaker by tripping of the mechanism and rotation of the bar,
each pole comprising a pair of separable contacts having a series of elementary contact fingers cooperating with a stationary contact in the closed position, an arc chute, an insulating cage supporting the contact fingers, and a pair of connection pads electrically connected to the separable contacts.
In a range of molded insulating case circuit breakers for low voltage systems, a plurality of types of poles are involved the structure of which depends on various factors, notably the rating, breaking capacity, discrimination, etc. . . The choice of a circuit breaker is made in such a way that:
their rating is at least equal to the rated current of the feeder involved,
their breaking capacity is at least equal to the short-circuit current calculated at the level considered,
discrimination with the downstream protective switchgear unit can be ensured.
It is therefore necessary to provide a first series of standard circuit breakers for standard service conditions to be used when the short-circuit power of the system does not require a high breaking capacity and full discrimination is not called for, a second series of limiting circuit breakers with high breaking capacity and electrodynamic self-repelling contacts, and a third series of discriminating trip release circuit breakers having a good electrodynamic contact withstand. This variety of types of poles makes manufacturing and managing such a range of circuit breakers complicated, and this gives rise to stocking and assembly cost problems.
The object of the invention consists in improving management of manufacturing a range of insulating molded case circuit breakers, by quick interchangeability of the poles when assembly takes place.