GB659025A - Improvements in or relating to high tension on-load transformer tap-changing switches - Google Patents

Abstract

659,025. Electric transformers. SMIT & CO.'S TRANSFORMATORENFABRIEK N.V., W. Aug. 8, 1949, No. 20569. Convention date, Aug. 9, 1948. [Class 38 (ii)] [Also in Group XXXVII] In a transformer on-load tapchanging switch having a main contact 2, connected directly to the line and adapted to be moved step-bystep over fixed contacts 4, 5, &c. and auxiliary contacts 1, 3 connected to the line through resistances and adapted to assist the change-over, the main and auxiliary contacts are operated successively and are mounted on concentric rotary shafts so as to trace out circles lying in different planes. In the form shown the main contact 2 is mounted on a rotary shaft 13 and sweeps over the fixed contacts 4, 5, 6, 7 while the contacts 1, 3 are fixed on the rotary sleeve 12 and sweep over contacts 4<SP>1</SP>, 51, 6<SP>1</SP>, 7<SP>1</SP> electrically connected to the contacts 4, 5, 6, 7. The desired sequence of operation is achieved by the use of Maltese crosses 14, 15 fixed to the parts 12, 13 and operated by pins 18, 18<SP>1</SP> and 19 on members 16, 17 driven by the common shaft 20. The complete cycle of operation from one contact to the next thus takes place in three successive stages, viz. contacts 1 and 3 move to form with their resistances a bridge between 4<SP>1</SP> and 51, contact 2 moves to contact 5, contacts 1 and 3 move on further till they are both on contact 5<SP>1</SP>. In a modification, Figs. 3 and 6 (not shown), the contacts 1, 2 and 3 are mounted on three concentric shafts and move successively.