GB710183A - On-load changeover switch for tapped transformers - Google Patents

Abstract

710,183. Regulating switches. JANSEN, B. March 22, 1951, No. 6935/51. Class 38(5) An on-load transformer tap-changing switch comprises fixed contacts Ha, ha, hb, Hb, and movable contacts K1 ... K3 which are subject to a compound movement comprising a steady primary movement transmitted from a driving member An and a superimposed unsteady movement impressed by each closed contact on the remaining movable contacts by means of a guide L common to the movable contacts. The latter are mounted on a circle Ti having 12 teeth and arranged to roll round the inside of a circle Ta having 16 teeth and carrying the fixed contacts, of which ha and hb are connected by resistances Wa, Wb to contacts Ha, Hb, in turn connected to transformer tappings A, B. To change over contact K1 from contact Ha (Fig. 1A) to Hb (Fig. 1G), the driving member An is rotated clockwise about the axis M of circle Ta, thus causing circle Ti to roll clockwise around the circle Ta, the following switching sequence taking place. Contact K2 is brought into engagement with contact ha before K1 separates from Ha, contact K3 is brought into engagement with hb before K2 separates from ha and K1 engages Hb before K3 separates from hb. The contacts K1 ... K3 are interconnected by push rods L1 ... L3 and the guide member L and are radially slidable in the circle Ti, so that as .each contact in turn engages a fixed contact it is moved radially inwards, the interconnecting means causing simultaneous withdrawal of the other two movable contacts, this movement constituting the superimposed unsteady movement. The contacts are biased outwards by a spring F. In a modification, Fig. 2 (not shown), the guide L is a pin slidable in a slot in a radial driving member An, the spring F being arranged between the outer end of the member An and the pin L. In a further modification, Fig. 3, the contacts are arranged in two groups, one of .each group such as K1, K2, being closed at the same time. Each group has its own guide member Sa or Sb, these members being interconnected by the spring F.