Electromechanical circuit breaker and method of breaking the current in said electromechanical circuit breaker

摘要

The electromechanical circuit breaker is intended to establish and break the current in a main circuit (3, 4) and comprises a fixed contact element (5) and a moving contact element (6) which in a first position are in electrical contact with each other for carrying the current of the main circuit (3, 4). Said moving contact element (6) is adapted to be displaced to a second position in which it is separated from the fixed contact element (5) so that the current in the main circuit is cut off. The circuit breaker is provided with a blow-out device (2) comprising a magnetising coil (8) traversed by a magnetising current for producing a magnetic field (26) adapted to drive an arc generated by the separation of said two contact elements (5, 6) into an arc extinction means. The blow-out device (2) comprises electrodes (12) electrically connected to the magnetising coil (8) and adapted to cooperate with said arc in such a manner that the latter generates said magnetising current in the magnetising coil (8). The magnetic field for driving the arc is generated by the action of said arc. Said electrodes (12) are located in such a relationship with said contact elements (5, 6) that the arc generated by the separation of said two contact elements is at least partially separated into a first arc (13a) between one contact element (5) and the electrodes (12) and a second arc (13b) between the electrodes (12) and the other contact element (6). Said first or second arc (13a, 13b) is set in parallel coupling with said magnetising coil (8) connected on one side to the electrodes (12) and on the other side to one of the contact elements (5, 6). These features allow to obtain high breaking efficiency and performances even when breaking smaller currents.