An electromagnetic trip unit, wherein: the electromagnetic trip unit includes a movable core, an upper static core and a lower static core; the movable core can move relative to the upper static core and the lower static core in the upper static core and the lower static core; a movable core body end of a movable core body of the movable core faces and approaches the lower static core end of the lower static core, when the electromagnetic trip unit is not released, a first magnetic field air gap is formed between the movable core body end and the lower static core end; the movable core body of the movable core is also provided with a movable core body step, when the electromagnetic trip unit is not released, a second magnetic field air gap is formed between the movable core body step and the lower static core end.

In present disclosure, a movable bar guide portion is formed to protrude toward a movable bar in a shaft having a movable bar, and when a fault current is applied and the movable bar is rotated due to electromagnetic repulsion force, the movable bar and the movable bar guide portion contact each other, and thus, when the movable bar is rotated through the movable guide portion, movement of a rotation center of the movable bar is minimized.

A low-voltage circuit breaker, including: at least one fixed contact, for each pole, which is electrically connected to a terminal for connection to an electric circuit and a corresponding moving contact which is associable/separable with respect to the fixed contact by means of a rotation of the moving contact; an arc chamber positioned in correspondence of the fixed contact; a rotating contact supporting shaft common to all poles, which is functionally connected to an actuation mechanism of the circuit breaker, the actuation mechanism including a kinematic system operatively connected to an actuation lever for opening/closing operations and provided with opening springs and a tripping shaft for releasing the kinematic system and allowing its movement from a closed to an open position. The low-voltage circuit breaker includes for each pole a quick acting trip device including a plunger inserted in a first channel connected to an arc chamber of the corresponding pole, the first channel being positioned proximate to the at least one fixed contact with its longitudinal axis perpendicular to the axis of the rotating contact supporting shaft, the plunger having a first operative surface subjected to the pressure of the arc chamber and a second operative surface, the quick acting trip device further includes a trip lever having a first portion cooperating with the tripping shaft and a second portion cooperating with the second operative surface of the plunger.

A restoring element is for an electrical switch. In an embodiment, the restoring element is constructed in two parts from a first part and a second part. The two parts are configured to converge in a first direction for tripping the electrical switch and the two parts do not necessarily converge in a second direction for resetting the electrical switch, the second direction being different from the first direction. Further, the second part of the restoring element includes a restoring cam which is configured to interact with a handle of a switching mechanism of the electrical switch, such that, during resetting of the electrical switch, the restoring element is configured to be rotated by the handle in the second direction for resetting the electrical switch.

A pressure trip unit for an electrical switch, including an actuating element and at least one flow channel per electrical pole, is disclosed. In an embodiment, the at least one pole of the electrical switch includes at least two switching contacts for making or disconnecting a flow path. The switching contacts of the at least one pole of the electrical switch are disconnectable via the actuating element which can respond to a pressure generated in a disconnection zone of the, in each case, two switching contacts by an electric arc drawn in the event of an electrodynamic recoil of the switching contacts. Further, the disconnection zone is connectable to the actuating element via the flow channel, the at least one flow channel including a nonreturn valve to permit a flow only from the disconnection zone in the direction of the actuating element.

A device for recognizing an arcing fault in incident light that includes a sensor for detecting absorption lines of the incident light, and an evaluation unit which generates an evaluation signal when characteristic absorption lines are detected.

A trigger element includes an actuating member of a pressure trigger for an electric switch. The pressure trigger is provided with at least one flow channel per electric pole. The at least one pole of the electric switch includes at least two switch contacts for making or breaking a current path. The switch contacts of the at least one pole of the electric switch is disconnectable via the actuating member, which can respond to a pressure that is generated by an electric arc drawn during electrodynamic recoil of the switch contacts in a separation zone of the two switch contacts. The separation zone is connectable to the actuating member via the flow channel such that the actuating member is guided from a housing of the trigger element between a neutral position and a trigger position. After the trigger position has been reached, a relief of pressure vents the pressure trigger.

A single- or multi-pole power circuit-breaker, comprises main contacts, overload- and/or short-circuit current-actuated tripping means, an actuating mechanism for the main contacts, an arc chute and a pressure trip unit having a return element and an actuating element responsive to an overpressure in the arc chute. The tripping of the power circuit-breaker by a trip mechanism is executable both by the tripping means and the pressure trip unit. The pressure trip unit is arranged immediately adjacently to both the arc chute and a main busbar. A tripping lug mechanically engages with the trip mechanism such that an overpressure in the arc chute is transmitted virtually instantaneously to the pressure chamber. The actuating element is configured to switch over directly from a home position to a tripping position, against the force of the return element, in a case of overshoot of a pressure threshold value set by the return element.

An electromagnetic trip unit, wherein: the electromagnetic trip unit includes a movable core, an upper static core and a lower static core; the movable core can move relative to the upper static core and the lower static core in the upper static core and the lower static core; a movable core body end of a movable core body of the movable core faces and approaches the lower static core end of the lower static core, when the electromagnetic trip unit is not released, a first magnetic field air gap is formed between the movable core body end and the lower static core end; the movable core body of the movable core is also provided with a movable core body step, when the electromagnetic trip unit is not released, a second magnetic field air gap is formed between the movable core body step and the lower static core end.

A single- or multi-pole power circuit-breaker, comprises main contacts, overload- and/or short-circuit current-actuated tripping means, an actuating mechanism for the main contacts, an arc chute and a pressure trip unit having a return element and an actuating element responsive to an overpressure in the arc chute. The tripping of the power circuit-breaker by a trip mechanism is executable both by the tripping means and the pressure trip unit. The pressure trip unit is arranged immediately adjacently to both the arc chute and a main busbar. A tripping lug mechanically engages with the trip mechanism such that an overpressure in the arc chute is transmitted virtually instantaneously to the pressure chamber. The actuating element is configured to switch over directly from a home position to a tripping position, against the force of the return element, in a case of overshoot of a pressure threshold value set by the return element.