GB514388A - Improvements in or relating to tap changing gear for electric transformers - Google Patents

Abstract

514,388. Regulating switches. GENERAL ELECTRIC CO., Ltd., and BOOKER, F. May 3, 1938, No. 13178. [Class 38 (v)] In a selector switch arrangement for onload tap changing gear for transformers, contacts of a pair of selector switches are rotated about the same axis by a common operating shaft and alternately advance from one tap connection to the next. Two insulating panels 1, 2 spaced apart by rods 3, carry eight contact rods 4 provided with terminals 5 and spaced apart at 30 degree intervals in an arc of a circle at the centre of which is an operating rod in two parts 7, 8 joined together by an insulating coupling 9. The parts 7, 8 carry respectively eccentrics 10, 11 upon which are rotatably mounted members 12, 13 carrying contact fingers 14, 15 which engage the fixed contact rods 4. Eccentrics 10, 11 are arranged at 180 degrees to one another, and members 12, 13 carry pins 16, 17 which cooperate with radial slots formed bv projections 18, 19 upon the panel; the central line of a slot bisecting the angle between two adjacent contact rods 4. Connection is made to the moving contacts by springs 20, 21 bearing on the parts 7, 8 and connected to terminals 22, 23. Upon rotation of the shaft in an anti-clockwise direction from the position shown in Fig. 2, the motion of the eccentric 10 moves down the member 12, the contacts 14 leave the fixed contact rod 4, and pin 16 enters a slot between projections 18. The member 12 then swings round and up, until the contacts 14 engage the next contact rod 4. The eccentric 11 moves member 13 but being spaced 180 degrees apart from eccentric 10, contacts 15 are always open when contacts 4, 14 are closed and vice versa.