An on-load tap-changer of a tap-changing transformer has a switch. The switch has: a take-off contact; a primary fixed contact; and a contact unit. The contact unit has a moving contact, a first arcing contact and a second arcing contact. These contacts are pivotable about a pivot axis during a switchover process such that the contacts assume a first position, in which they make contact with the take-off contact and the primary fixed contact, and a second position, in which they are separated from the take-off contact and the primary fixed contact. The second arcing contact assumes the first position before the first arcing contact when switching over from the second position to the first position and leaves the first position after the first arcing contact when switching over from the first position to the second position.

An on-load tap-changer of a tap-changing transformer has a switch. The switch has: a take-off contact; a primary fixed contact; and a contact unit. The contact unit has a moving contact, a first arcing contact and a second arcing contact. These contacts are pivotable about a pivot axis during a switchover process such that the contacts assume a first position, in which they make contact with the take-off contact and the primary fixed contact, and a second position, in which they are separated from the take-off contact and the primary fixed contact. The second arcing contact assumes the first position before the first arcing contact when switching over from the second position to the first position and leaves the first position after the first arcing contact when switching over from the first position to the second position.

A system includes a mechanical switching device having a first moveable contact operatively connected to selectively contact a first static contact. A second moveable contact is operatively connected to selectively contact a second static contact that is electrically connected in parallel with the first static contact. The first and second moveable contacts are mechanically connected to each other to move between a closed circuit position and an open circuit position. The first moveable contact contacts the first static contact before the second moveable contact contacts the second static contact as the first and second moveable contacts move into the closed circuit position from the open circuit position. The first moveable contact disconnects from the first static contact after the second moveable contact disconnects from the second static contact as the first and second moveable contacts move from the closed circuit position into the open circuit position.

A system including an arc flash sensor that detects an arc flash event and an arc flash mitigation device in communication with the sensor. The mitigation device includes a path of least resistance having a path input and a path output. The arc flash sensor is located downstream the output. The mitigation device includes an electro-mechanical switch between the input and the output and an actuator. The mitigation device also includes a bypass power switch device that includes a solid-state circuit interrupter and that conduct current between the input and the output in response to an open-circuit condition of the switch. A system controller is provided to generate a trigger to activate the actuator to generate the open-circuit condition of the switch, which causes the power switch device to interrupt a fault current associated with a fault event in response to detection of the arc flash event.

A system including an arc flash sensor that detects an arc flash event and an arc flash mitigation device in communication with the sensor. The mitigation device includes a path of least resistance having a path input and a path output. The arc flash sensor is located downstream the output. The mitigation device includes an electro-mechanical switch between the input and the output and an actuator. The mitigation device also includes a bypass power switch device that includes a solid-state circuit interrupter and that conduct current between the input and the output in response to an open-circuit condition of the switch. A system controller is provided to generate a trigger to activate the actuator to generate the open-circuit condition of the switch, which causes the power switch device to interrupt a fault current associated with a fault event in response to detection of the arc flash event.

A relay contactor is provided and includes a shaft assembly comprising a plate, which is movable between an open position at which the plate is displaced from leads and a closed position at which the plate contacts the leads and an actuation system configured to selectively move the plate into the closed position. At least one of the shaft assembly and the actuation system is configured such that, as the plate moves into and away from the closed position, a movement of the plate relative to the leads comprises at least a non-linear, rotational or an abnormally linear component.

An on-load tap changer has a contact system. The contact system includes: a fixed contact; a movable contact; and an auxiliary contact. The moveable contact is configured to directly contact, in a stationary state, the fixed contact. The auxiliary contact is configured to electrically connect, in addition to the direct contact, the movable contact with the fixed contact in the stationary state. The auxiliary contact is constructed and arranged to conduct a current between the fixed contact and the movable contact in the event of interruption of the direct contacting.

An on-load tap changer has a contact system. The contact system includes: a fixed contact; a movable contact; and an auxiliary contact. The moveable contact is configured to directly contact, in a stationary state, the fixed contact. The auxiliary contact is configured to electrically connect, in addition to the direct contact, the movable contact with the fixed contact in the stationary state. The auxiliary contact is constructed and arranged to conduct a current between the fixed contact and the movable contact in the event of interruption of the direct contacting.

A mechanical cut-off apparatus of a high-voltage electric circuit includes: in a main electrical path a main mechanical switch; in a secondary electrical path, a secondary mechanical switch; a mechanical control configured such that, the secondary mechanical switch is brought to its mechanically open state after the main mechanical switch has been brought to its mechanically open state; the apparatus includes a transition dipole comprising a capacitance, the transition dipole arranged in series with the pair of secondary electrical contacts in the secondary electrical path, and in that the apparatus includes a controlled switch which, in an electrically closed state, creates inside the mechanical cut-off apparatus a bypass that short-circuits the capacitance of the transition dipole.

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.