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 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.

An arc chamber for a low voltage switching device including an insulating casing, having a first and a second lateral walls, a rear and a front wall, that defines an internal space housing a number or arc-breaking plates, a top wall of the casing having a discharge opening for venting off the gases from the internal space, the discharge opening being covered by a top cover. The arc chamber for a low voltage switching device includes a filter made of an open cell metal foam that is positioned at the discharge opening.

An arc chamber 10, 20, 30, 40, 50 for a low voltage switching device comprising an insulating casing 1, having a first and a second lateral walls 2,3, a rear and a front wall 4,5, that defines an internal space housing a number of arc-breaking plates, a top wall 6 of said casing having a discharge opening 101 for venting off the gases from said internal space, said discharge opening 101 being covered by a top cover 7, 37, 47, 57. The arc chamber for a low voltage switching device comprises a filter 11, 21, 31, 41, 51 made of an open cell metal foam is positioned at said discharge opening 101.

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.

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 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.

In some aspects, a relay assembly having an exhaust cover is provided. The relay assembly can include a housing, a relay enclosed within the housing, and the exhaust cover. The exhaust cover can be positioned in an opening of the housing that is adjacent to the relay. The exhaust cover can move in a direction away from the relay in response to a pressure generated inside the housing by the relay being communicated to the exhaust cover.