An arc box and an electromagnetic contactor comprising same are disclosed. The arc box according to an embodiment of the present disclosure comprises a coupling protrusion. The coupling protrusion is inserted into and coupled to a grid coupling hole of an arc chamber. Therefore, the arc chamber can be stably coupled to the arc box. In one embodiment, the coupling can be performed through snap fastening. Therefore, the arc chamber and the arc box can be easily coupled. A rib part is formed on the arc box. The rib part is positioned to be adjacent to the coupled arc chamber so as to prevent pitching of the arc chamber. Therefore, the arc chamber coupled to the arc box can stably maintain a stopping state.

An air circuit breaker is disclosed. The air circuit breaker according to an embodiment of the present disclosure includes a cover magnet unit. The cover magnet unit is directly coupled to an upper cover which forms the outer appearance of the air circuit breaker. The cover magnet unit is positioned adjacent to a fixed contact and forms a magnetic field. Due to the formed magnetic field, an electromagnetic force in a direction toward an arc extinguishing unit is applied to a generated arc. Accordingly, the generated arc may be rapidly moved and extinguished. The cover magnet unit is inserted into a surface of the upper cover and is not exposed to the outside. Therefore, the generated arc is not in contact with the cover magnet unit. As a result, the cover magnet unit is not damaged by the generated arc.

The present disclosure relates to an arc extinguishing assembly which, when an arc is generated, has a structure that can push the generated arc in a direction farther away from a stationary contact point by forming a transient pressure difference between arc guides.

The present disclosure relates to an arc extinguishing assembly including a sealing member and a circuit breaker including same. The sealing member is pressed and elastically deformed between coupling surfaces of the arc extinguishing assembly and the circuit breaker, and accordingly, a gap between the coupling surfaces of the arc extinguishing assembly and the circuit breaker is sealed. Accordingly, when an arc is generated, a temporary pressure increase in the circuit breaker increases and the arc can be smoothly extended.

Disclosed is an air circuit breaker. The air circuit breaker according to an embodiment of the present disclosure includes a CT magnet unit. The CT magnet unit is provided in the air circuit breaker to cover a movable contact point exposed to the outside. A CT magnet is provided inside a case that forms the outer shape of the CT magnet unit. The CT magnet independently forms a sub magnetic field or forms a main magnetic field together with an extinguishing magnet provided in an arc extinguishing unit. Due to the magnetic field formed by the CT magnet, an arc that is generated receives the application of an electromagnetic force directed toward the arc extinguishing unit. Accordingly, the generated arc can be quickly moved and extinguished.

An arc extinguishing unit and an air circuit breaker comprising same are disclosed. An arc extinguishing unit, according to an embodiment of the present disclosure, comprises an extinguishing magnet unit that forms a magnetic field inside the arc extinguishing unit. Accordingly, a generated arc receives an electromagnetic force in the direction facing the exterior of the air circuit breaker, and thus can be rapidly moved and extinguished. The extinguishing magnet unit is accommodated in a magnet case. The magnet case can seal the extinguishing magnet unit. Therefore, the extinguishing magnet unit is not damaged by the generated arc.

A circuit interrupter has first and second contacts that are actuatable relative to each other between a closed position wherein a power source and a load are in electrical communication and an open position wherein the power source and the load are not in electrical communication. An arc extinguisher is also provided for extinguishing an arc that develops in the vicinity of the contacts. An electromagnetic coil, when energized, generates a magnetic field that permeates an area where the arc develops, the magnetic field urging the arc toward the arc extinguisher regardless of a polarity of the contacts. An auxiliary switch is operably connected to the contacts, such that upon movement of the contacts relative to each other from the closed position toward the open position, the auxiliary switch is activated so as to energize a circuit feeding power to the electromagnetic coil, thereby generating the magnetic field.

The present disclosure relates to an arc extinguishing assembly, including side members which are spaced apart by a certain distance and disposed to face each other; an exhaust which is installed at an upper part of the side member; a plurality of grids which are installed between the side members and having both ends fixed to each of the side members; and an arc guide whose one side is coupled to the side member and which is installed at a lower part of the plurality of grids, wherein the arc guide is made of a material having heat resistance, and a circuit breaker including the same.

An arc extinguishing unit and an air circuit breaker comprising same are disclosed. The arc extinguishing unit according to an embodiment of the present disclosure comprises an arc extinguishing magnet located above a grid. The arc extinguishing magnet forms a magnetic field in the arc extinguishing part and in a fixed contact and a movable contact that are located adjacent to the arc extinguishing part. An arc generated as the fixed contact and the movable contact are separated from each other receives an electromagnetic force in the formed magnetic field. The electromagnetic force passes through the grid and is formed in a direction facing the exterior of the arc extinguishing part. Thus, the generated arc may be quickly extinguished and moved.

An electric arc extinction chamber comprises a stack of electric arc splitter plates. The splitter plates define an inlet of the extinction chamber that is to be present facing electric contacts, and a back of the extinction chamber. At least one permanent magnet is present inside the extinction chamber in a central zone in the width direction of the extinction chamber and beside the back thereof. The magnet presents magnetization having a non-zero component along an axis extending between the inlet and the back of the extinction chamber.