METHOD AND SYSTEM FOR A PRE-SELECTOR IN A TAP CHANGER

摘要

A pre-selector of a tap changer is provided with an operating arrangement, which provide varying speed for the movable contact of the pre-selector. The arrangement is provided in a cylindrical tap changer (10) that includes a cylinder (24) provided with tap contacts and pre-selector contacts (25-27) extending inside the cylinder, the arrangement comprises a contact carrier (9) provided with at least one movable contact (8) for mating the pre-selector contacts of the cylinder (24), and a drive mechanism (21) for providing a rotational movement to the contact carrier (9), which contact carrier (9) during use is rotated by means of the drive mechanism (21) so that the movable contact (8) selectively mate with the pre-selector contacts (25-27) on the inside of the cylinder. The arrangement is characterised in that the drive mechanism (21) is operatively connected to the contact carrier (9) via a staggering mechanism (1) arranged to provide a rotation with varying angular velocity to the contact carrier (9).