A switch device includes: an operation unit including a first switch, a second switch, a first resistor, a second resistor, and a first terminal; and a control unit including a second terminal coupled to the first terminal. A series circuit of the first switch and the first resistor and a series circuit of the second switch and the second resistor are coupled between the first terminal and a ground. The control unit monitors a potential of the first terminal which changes in response to on/off of the first and second switches via the second terminal, and determines the operation state of each switch based on the potential. A contact of the first switch is configured of a contact in which a resistance value between contacts at the time of opening and closing changes more sharply as compared with a contact of the second switch.

A key entry device including a housing, a keypad array disposed within the housing and including a plurality of keys, a key contact array disposed within the housing below the keypad array and including a plurality of contact pairs, a dome array underlying the keypad array and the key contact array and including a plurality of domes, and a protrusion array underlying the dome array and including a plurality of protrusions, whereby depression of one of the plurality of keys of the keypad array causes a corresponding one of the domes of the dome array to be displaced downwardly and to be deformed by pushing engagement with a corresponding one of the protrusions of the protrusion array into contact with at least one of the contact pairs of the key contact array.

A system for isolating a fault in a direct current (DC) grid using thermionic arc extinction. The system includes a DC grid that includes a transmission line. The DC grid also includes a plurality of current interrupters disposed on the transmission line. Each of the plurality of current interrupters on the transmission line are electrically coupled to one another in series. At least one of the current interrupters includes a fixed terminal end and a moveable terminal end. Further, at least one of the current interrupters has an arc shield housing at least two arcing contacts. At least one of the arcing contacts comprises a first conducting material that has a first vaporizing point.

An electrical contact device includes a high electric potential-side contact and a low electric potential-side contact having a lower electric potential than the high electric potential-side contact. The high electric potential-side contact and the low electric potential-side contact are configured to be brought into and out of contact with each other. At least one of the high electric potential-side contact and the low electric potential-side contact is formed of a low-boiling point material whose boiling point is lower than 2562° C. or a mixed material that contains the low-boiling point material.

This invention relates to a telescopic switch for isolated-phase bus duct, comprising: a first male conductor including a first guide-positioner means (4); a 5 second female lead connector coaxially separated from the first connector which includes a second guide-positioning means, wherein said moving contact is coupled coaxially and in a movable manner to the first conductor, and wherein said moving contact moves to an open position, wherein said moving contact is separated from the first conductor and to a closed position where said moving contact causes a contact between the first male connector and that of a second female connector, through interaction with one another from the first guide-positioner means of the first conductor, the second guide-positioner means of the second conductor and the guiding means of the moving contact.

A system for isolating a fault in a direct current (DC) grid using thermionic arc extinction. The system includes a DC grid that includes a transmission line. The DC grid also includes a plurality of current interrupters disposed on the transmission line. Each of the plurality of current interrupters on the transmission line are electrically coupled to one another in series. At least one of the current interrupters includes a fixed terminal end and a moveable terminal end. Further, at least one of the current interrupters has an arc shield housing at least two arcing contacts. At least one of the arcing contacts comprises a first conducting material that has a first vaporizing point.

The present disclosure relates to an electromechanical switching device comprising switching contacts configured to close an electrical circuit, wherein the switching contacts have a first switching contact and a second switching contact, wherein the first switching contact and the second switching contact can be brought into contact in order to close the electrical circuit, wherein at least one of the switching contacts s formed from a plurality of closed bodies which are arranged against one another, and wherein hollow spaces for receiving liquid are arranged between the closed bodies.

A device for thermionic arc extinction via anode ion depletion. The device includes a body including an inner compartment. The inner compartment includes at least an arc shield housing at least two arcing contacts, wherein the two arcing contacts are zinc-plated. The at least two zinc-plated arcing contacts further comprise a thickness and contact area customized based on a desired corrosion time of the zinc, wherein the corrosion time corresponds to extinction of the arc. A sensor is associated with the device. The sensor is configured to operate the movement of the at least two arcing contacts.

A key entry device including a housing, a keypad array disposed within the housing and including a plurality of keys, a key contact array disposed within the housing below the keypad array and including a plurality of contact pairs, a dome array underlying the keypad array and the key contact array and including a plurality of domes, and a protrusion array underlying the dome array and including a plurality of protrusions, whereby depression of one of the plurality of keys of the keypad array causes a corresponding one of the domes of the dome array to be displaced downwardly and to be deformed by pushing engagement with a corresponding one of the protrusions of the protrusion array into contact with at least one of the contact pairs of the key contact array.

A system for isolating a fault in a direct current (DC) grid using thermionic arc extinction. The system includes a DC grid that includes a transmission line. The DC grid also includes a plurality of current interrupters disposed on the transmission line. Each of the plurality of current interrupters on the transmission line are electrically coupled to one another in series. At least one of the current interrupters includes a fixed terminal end and a moveable terminal end. Further, at least one of the current interrupters has an arc shield housing at least two arcing contacts. At least one of the arcing contacts comprises a first conducting material that has a first vaporizing point.