Abstract: Snap-action spring device for load-reversing switches of multiple contact switches whose spring can be loaded by a drive. In conventional load-reversing switches, a gear moves a cam disk to and fro between two end positions, so that the contacts which close last during the movement in one direction are the first to open during the reverse movement and vice versa. This rigid sequence of contacts is unsuitable for thyristor load-reversing switches. The invention proposes that the driven element be connected to a coupling element which can rotate in one direction only independently of the direction of rotation of the drive. This permits automatic contact sequence control and precludes switching errors, in a simpler manner.

Abstract: The invention relates to a circuit arrangement for switching current from a contact to a thyristor connected in parallel to the contact. In the inventive circuit arrangement ohmic resistances (7, 8, 9, 10) are connected in parallel to the contact (1), whereby each ohmic resistance (7, 8, 9, 10) can be individually disconnected by means of a delayed-opening contact (3, 4, 5, 6) and the disconnection times are staggered. In this manner, it is possible to accomplish stepwise current switching and thus reliably prevent arcing at the contact (1).

Abstract: The invention relates to an arrangement in an on-load change-over switch of an on-load tap changer for uninterrupted switch-over of the regulating winding of a transformer. On-load change-over switching is usually accomplished using mechanical switching elements. Burning of contact and contamination of oil are disadvantageous. Furthermore, there are known constructions which use a combination of mechanical switching elements and thyristors for on-load change-over switching. The disadvantage of such arrangements is mainly the too great constructional expenditure for the control elements which are liable to breakdown.