The invention relates to a switch assembly (1), in particular a preselector, for a variable transformer (4) having a first winding (2) and a second winding (3) with a first and a second tap (3.3, 3.4), said switch assembly comprising: a first connection terminal (2.1) that can be connected to the first winding (2); a second connection terminal (3.1) that can be connected to the first tap (3.3); a third connection terminal (3.2) that can be connected to the second tap (3.4); a first, second, third and fourth fixed contact (5.1, 5.2, 5.3, 5.4); a vacuum interrupter (6); a first moving contact (7) that can be contacted selectively with the first or second fixed contact (5.1, 5.2); a second moving contact (8) that can be contacted selectively with the third or fourth fixed contact (5.3, 5.4), wherein the second and the fourth fixed contact (5.2, 5.4) are connected to the second connection terminal (3.1), the first and the third fixed contact (5.1, 5.3) are connected to the third connection terminal (32) the first moving contact (7) is connected to the first connection terminal (2.1) via the vacuum interrupter (6), and the second moving contact (8) is connected to the first connection terminal (2.1).

A switch includes a diverter contact; a primary fixed contact; and a secondary fixed contact. The switch additionally includes a primary movable contact configured to be pivoted, relative to the diverter contact and the primary fixed contact, about a pivot axis between a first end position and a second end position. In the first end position, the primary movable contact bears by a first contact point against the diverter contact and by a second contact point against the primary fixed contact. The switch further includes a secondary movable contact configured to be pivoted, relative to the diverter contact and the secondary fixed contact, about the pivot axis between a first end position and a second end position. In the first end position the secondary movable contact bears by a third contact point against the diverter contact and by a fourth contact point against the secondary fixed contact.

A switch includes a diverter contact; a primary fixed contact; and a secondary fixed contact. The switch additionally includes a primary movable contact configured to be pivoted, relative to the diverter contact and the primary fixed contact, about a pivot axis between a first end position and a second end position. In the first end position, the primary movable contact bears by a first contact point against the diverter contact and by a second contact point against the primary fixed contact. The switch further includes a secondary movable contact configured to be pivoted, relative to the diverter contact and the secondary fixed contact, about the pivot axis between a first end position and a second end position. In the first end position the secondary movable contact bears by a third contact point against the diverter contact and by a fourth contact point against the secondary fixed contact.

A method of controlling at least one switching module having commutation cells which are associated with a regulating winding of a regulating transformer, the commutation cells including: a first and second switching element each having two thyristors in antiparallel connection.

An on-load tap-changer provides uninterrupted diverter switch operation between different winding taps of a tap-changing transformer. The on-load tap-changer includes: a flange module; and a union nut. The on-load tap-changer is configured to be fastened to the tap-changing transformer by the union nut and the flange module.

An on-load tap-changer provides uninterrupted diverter switch operation between different winding taps of a tap-changing transformer. The on-load tap-changer includes: a flange module; and a union nut. The on-load tap-changer is configured to be fastened to the tap-changing transformer by the union nut and the flange module.

An apparatus for a load tap changer includes a first primary winding electrically connected to a first contact, the first contact configured to connect to one of a plurality of taps in a load tap changer; a second contact, the second contact configured to connect to one of the plurality of taps in the load tap changer; a magnetic core; and a control circuit including: a secondary winding configured to magnetically couple to the first primary winding and the magnetic core; and an electrical network electrically connected to the secondary winding, the electrical network being configured to prevent magnetic saturation of the magnetic core during switching of the first or second contact.

A phase shifting transformer for poly-phase alternating current includes source side terminals, load side terminals, an exciting unit, and a series unit. The exciting unit includes further coils that are magnetically coupled to primary coils and to the secondary coils of the exciting unit to provide further voltages. The further coils are connected in series between the source side terminals and the series unit, so that the voltages at the load terminals are combinations of the quadrature voltages and the further voltages with the source voltages, thus modifying the voltage phase displacement between the source side terminals and the load side terminals.

A phase shifting transformer for poly-phase alternating current includes source side terminals, load side terminals, an exciting unit, and a series unit. The exciting unit includes further coils that are magnetically coupled to primary coils and to the secondary coils of the exciting unit to provide further voltages. The further coils are connected in series between the source side terminals and the series unit, so that the voltages at the load terminals are combinations of the quadrature voltages and the further voltages with the source voltages, thus modifying the voltage phase displacement between the source side terminals and the load side terminals.

An on-load tap changing apparatus includes a first switching unit connected to a first tap of a transformer provided in a power system and switching power supplied from the first tap, a first impedance changing unit connected in series with the first switching unit and increasing an impedance when the first switching unit executes a switching operation, a second switching unit connected to a second tap of the transformer and switching power supplied from the second tap, and a second impedance changing unit connected in series with the second switching unit and increasing an impedance when the second switching unit executes a switching operation. The on-load tap changing apparatus can suppress an arc at the time of switching, reduce deterioration of a switching unit, and have excellent durability.