VUC Series Tap-changers Technical guide

Overview

On-load tap-changer (OLTC)

VUC vacuum diverter switch tap-changer family comes in a range of models with ratings suitable for the most frequent transformer applications. The VUC types of tap-changers are usually mounted inside the transformer tank, suspended from the transformer cover.

VUC tap-changers is built on the same platform as the conventional UC tap-changers and shares the well proven selectors, diverter switch housings and drive train.

This design consists of two separate sections: the diverter switch, which has its own housing separate from the rest of the transformer, and the tap selector. The tap selector, which is mounted beneath the diverter switch housing, consists of the fine tap selector and usually also of a change-over selector.

Power to operate the tap-changer is supplied from the motor drive mechanism, which is mounted on the outside of the transformer. The power is transmitted by means of shafts and bevel gears.

The VUC diverter switches, with arc quenching in vacuum interrupters, contaminates it’s insulating liquid slightly due to current commutation sparks and heat dissipation from the transition resistors therefore it’s insulating liquid is kept separated from the oil in the transformerto not influence the oil analysis of the main transformer tank.