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 switching device includes: a first terminal contact; a first fixed contact arranged at the first terminal contact; a contact bridge; a contact bridge carrier arranged at the contact bridge and having a barrier; a first movable contact arranged at the contact bridge; a second terminal contact; a second fixed contact arranged at the second terminal contact; a second movable contact arranged at the contact bridge; and a magnetic drive assembly including a coil and an armature, the armature being coupled to the contact bridge. The first fixed contact is in contact with the first movable contact in a switched-on state of the switching device. The first fixed contact is free of contact with the first movable contact in a switched-off state of the switching device. The second fixed contact is in contact with the second movable contact in the switched-on state of the switching device.

Currents may be balanced in an apparatus including first and second conductors electrically connected to a third conductor and configured to be coupled to respective first and second parallel-connected circuit breaker switches using at least one magnetic core positioned adjacent at least one of the first and second conductors to introduce an inductance in the at least one of the first and second conductors. The at least one core may include at least one magnetic material ring that at least partially surrounds the at least one of the first and second conductors. The at least one magnetic material ring may include a plurality of laminated layers of grain-oriented steel.

Systems of automatic transfer switches (ATS) are disclosed herein. One apparatus includes at least two automatic transfer switches coupled together. Each automatic transfer switches has contacts to couple a power source to a load. For each switch, an electromagnetic force biasing the contacts to each other is present if an electrical current flows through the switch. The automatic transfer switches may be on separate cassettes or on a single cassette. The power source of each switch may be the same or different.

A high-voltage relay includes a magnetic drive assembly having a first yoke and a second yoke spaced apart from one another, and an armature driven by the magnetic drive assembly. The armature is a rocker having a first arm and a second arm extending away from the first yoke. The armature can be tilted between an open position and a switching position and is mounted on the first yoke. The first arm has a switching contact assembly. A magnetic circuit including the first yoke and the second yoke is closed in the switching position by the second arm.

A high voltage, direct current circuit protection system includes a number n of weakened circuit conductors connected in series to one another and being fabricated in a manner to avoid metal fatigue in response to cyclic current loads. The system also includes a corresponding number n of cutting elements operable to sever the respective weakened circuit conductors, at least one energy storage element acting upon one of the cutting elements, a control element causing a release of stored energy in the at least one energy storage element and causing a displacement of at least one of the cutting elements to sever the respective weakened circuit conductor, and a corresponding number n of arc chambers arranged proximate each respective one of the weakened circuit conductors, wherein n is an integer greater than 1 and wherein no circuit protector coordination with the weakened circuit protectors is required.

A switch includes a first switch (100) including a first fixed contact (111) and a first movable contact (121) and a second switch (200) including a second fixed contact (211) and a second movable contact (221). The first fixed contact (111) and the first movable contact (121) come into contact and the second fixed contact (211) and the second movable contact (221) come into contact to turn on the switch. A magnet (320) is installed between the first switch (100) and the second switch (200).

Multiple relays are connected in parallel by including one or more semiconductor devices connected across the relay contacts. The semiconductor devices are triggered to conduct and shunt transient currents during the opening and closing of the relay contacts to protect the relay contacts from overcurrent and to eliminate arcing during relay switching. This permits a combination of smaller relays to replace a larger and more expensive relay in applications that require switching of large load currents.