An arc extinguishing device of a DC circuit breaker is proposed. The arc extinguishing device is provided with electromagnets installed on opposite sides of an arc extinguishing chamber, so as to increase arc resistance, thereby quickly extinguishing an arc. The arc extinguishing device includes: an arc extinguishing chamber installed above contact terminals and provided with an internal space formed open up and down; a plurality of grids installed side by side in the internal space of the arc extinguishing chamber; a cover installed on an upper part of the arc extinguishing chamber, and including a filter for filtering out impurities remaining in an arc which is extinguished in the arc extinguishing chamber; and electromagnets installed on the one side and the other side of the internal space of the arc extinguishing chamber.

A multi-finger circuit breaker includes a moving contact assembly having a carrier body, a first plurality of fixed breaking contacts, a first plurality of movable contacts, a plurality of first fingers, at least one second finger longer in length to a length of a first finger of the plurality of first fingers, a plurality of splitter plates disposed adjacent to the plurality of first fingers and the at least one second finger and a slot motor disposed adjacent to the plurality of first fingers and the at least one second finger. The slot motor is configured to provide a first magnetic field force to amplify a second magnetic field force being applied on the second finger to influence an arc between the first plurality of fixed breaking contacts and the first plurality of movable contacts during a short circuit such that to move the arc away from between the first plurality of fixed breaking contacts and the first plurality of movable contacts and dissipate energy of the arc.

An electromechanical switching device for breaking an electric current, the switching device including a stationary main contact; a movable main contact; a stationary arcing contact; a movable arcing contact, the stationary arcing contact and the movable arcing contact being arranged in parallel with the stationary main contact and the movable main contact; an actuating arrangement configured to move the movable main contact and the movable arcing contact; and a magnetic member arranged to generate a magnetic holding force in response to an electric current flow through the movable arcing contact when the movable arcing contact is in the closed position, the magnetic holding force acting on the movable arcing contact in a direction against the stationary arcing contact.

An electromagnetic switch includes a pair of fixed contacts disposed and fixed in a contact housing case with a predetermined distance therebetween; a movable contact disposed in the contact housing case so as to contact and separate from the pair of fixed contacts; and an electromagnet unit which brings the movable contact into and out of contact with the pair of fixed contacts. The electromagnet unit has a magnetic yoke enclosing an exciting coil, a movable plunger having a contact pole surface facing the contact pole surface of the magnetic yoke, and a linking shaft which links the movable plunger and the movable contact, and magnetic paths through which a holding force is generated by external magnetic fluxes generated by a flowing current when the movable contact contacts the pair of fixed contacts, are formed on the contact pole surface of the magnetic yoke.

A slot motor apparatus for a circuit breaker is disclosed. The slot motor has first and second legs connected by a thin web, and an extending portion extending rearward from the rear faces of the legs. Slot motor-arc plate assemblies having an arc plate assembly received at least partially overtop of the extending portion are also disclosed, as are assemblies having the arc plate assembly received very close to the rear faces of the slot motor legs. Circuit breakers, slot motor-arc plate assemblies, slot motor covers, and methods of operating the slot motor-arc plate assemblies are disclosed, as are other aspects.

A high-voltage DC relay with permanent magnet arc extinguishing function includes two static contact leading-out terminals having static contacts; a movable contact piece having movable contacts; first permanent magnets around the movable contact piece, wherein a side having polarity of the first permanent magnets faces the contacts such that arc extinction is implemented using a horizontal magnetic field formed by the first permanent magnets; and third permanent magnets provided on the static contact leading-out terminals, the polarity of the sides facing the contacts of the third permanent magnets is opposite to that of the first permanent magnets such that magnetic field strength at the contacts can be enhanced by a longitudinal magnetic field formed by the first and the third permanent magnets, and arc extinction can be implemented.