A spring unit includes a mechanical spring means having a spring direction and being located between a first spring support and a second spring support, which first and second spring supports are movable in relation to each other in the spring direction. The spring unit further includes a first actuation member facing the rear side of the first spring support and a second actuation member facing the rear side of the second spring support, which first and second actuating members are movable relative to each other and relative to the first and second spring supports in the spring direction.

Contact unit for a tap changer including a contact ring having a central axis, a plurality of fixed contacts arranged at a distance from the contact ring in different radial directions, and a moving contact arranged rotatable about the central axis of the contact ring and adapted to electrically connect the fixed contacts one at a time with the contact ring. The moving contact includes two elongated contact elements. Each of the contact elements includes a first contact area for providing electrical contact with the fixed contacts and a second contact area for providing electrical contact with the contact ring. The moving contact is designed so an electric path is formed between the first and second contact area. The first and second contact areas are positioned on opposite sides of a plane orthogonal to a longitudinal axis of the moving contact and including the central axis of the contact ring.

The present invention relates to a contact unit for changing over between winding taps on a control winding of a tapped transformer. Such a contact unit can be used particularly preferably for electrical switchgear in high-voltage engineering, such as selector switches or changeover switches. A common feature of both kinds of device in this case is that the changeover between the winding taps on the control winding of the tapped transformer is accomplished without load current. The general inventive concept is to include the contact element of the contact unit in a separate contact housing, so that the contact element and the contact housing form a separate assembly and so that the contact housing, including the contact element, can be fixed in a recess provided in the contact mounting by means of a retaining element.

A switching arrangement (1), in particular a polarity switching means, for a control transformer (10) which comprises a first winding (2) for a phase of an AC power supply system, which phase is to be controlled, comprises—a first connection terminal (1.1) which can be connected to the winding (2);—a second connection terminal (1.2) which can be connected to a discharge line (3);—a vacuum interrupter (4);—an isolator (5);—a resistor (6) which is connected in series with the vacuum interrupter (4) and the isolator (5); wherein—the first connection terminal (1.1) is connected to the second connection terminal (1.2) by means of the series circuit.

An on-load tap-changer for dry transformers, having an electric insulating hollow casing extending around a virtual axis, wherein several electric contact sections are foreseen along a path on the inner surface of the hollow casing, which are electrically joined through the wall of the hollow casing and a selector contact in the inner of the cylinder which is moveable along the path and that's outer end is selectively connectable with one of the contact sections by a respective movement. Respective cables are foreseen to electrically connect the contact sections from the radial outer side of the hollow casing, wherein at least some of the cables have a respective surrounding outer insulation at least at their respective connected end.

A contact bounce reduction system including: a movable member, and a contact bounce damping device including: a body, a first ball and a second ball, a first resilient member and a second resilient member, a piston. The first resilient member holds the first ball in the seat and the second resilient member holds the second ball in the seat when the piston is in a default extended position, and a third resilient member biases the piston towards the default extended position. The movable member actuates the piston towards the retracted position, causing the first ball and the second ball to move radially out from the seat, and the third resilient member to accumulate energy.

A spring unit includes a mechanical spring means having a spring direction and being located between a first spring support and a second spring support, which first and second spring supports are movable in relation to each other in the spring direction. The spring unit further includes a first actuation member facing the rear side of the first spring support and a second actuation member facing the rear side of the second spring support, which first and second actuating members are movable relative to each other and relative to the first and second spring supports in the spring direction.

The disclosure relates to a tap changer arranged to be connected to a regulating winding of a rated regulation voltage. The tap changer comprises a diverter switch, a tap selector and a set of tap changer contacts. The tap selector and the diverter switch are encapsulated in a shielding structure arranged to shield the tap selector and the diverter switch from an external electrical field, the shielding structure being arranged to be electrically connected to a connected tap of the regulating winding.

The disclosure further relates to transformer arrangement comprising at least one such tap changer.

An on-load tap changer includes: a fine selector, including: fixed contacts having a commutation contact, connectable with a main winding, and tap contacts, connectable with an associated tap of regulating windings; first and second arms that selectably contact the fixed contacts; a preselector, switchable between first and second settings, connectable with the regulating and main windings, and having: first, second, and third preselector fixed contacts, connectable in the first setting with the first preselector fixed contact and in the second setting with the second preselector fixed contact; and a load changeover switch, switchable between first and second changeover settings, and including: a first terminal connected with the first arm, a second terminal connected with the second arm, and a diverter line connected in the first changeover setting with the first terminal and in the second changeover setting with the second terminal.

The present invention relates to an On-Load Tap Changer (OLTC) for connection to a regulating winding of a transformer, the regulating winding enclosed in a transformer tank, wherein the transformer tank includes insulating liquid, the OLTC comprising: a switching device including: a main contact, and a resistor contact, wherein the main contact and the resistor contact are configured to be arranged directly in the insulating liquid and that they are configured to be physically separated from the insulating liquid, and wherein the main contact is enclosed in a main contact enclosure and the resistor contact is enclosed in a resistor contact enclosure. The present invention further relates to a transformer comprising the OLTC as disclosed herein.