GB733710A - Improvements relating to electrical selector switches - Google Patents

Abstract

733,710. Regulating switches. FERRANTI, Ltd. Feb. 5, 1954 [Feb. 7, 1953], No. 3511/53. Class 38 (5). An electrical regulating switch includes a moving contact member 10 comprising two helically shaped strips 12, 13 which form an incomplete turn of an external screw thread and which are spring urged together and secured to an insulative body 16 by a series of gimbal mountings 14, the body 16 being keyed to an operating shaft 20 so that it is capable of being rotated about the axis 11 of the screw thread and movement along this axis, the fixed contact members being formed by certain of the elements 30 which are mounted in banks 31-34 so that they define a screw thread which is complimentary to and coaxial with that formed by the moving contact member so that upon rotation of the shaft 20 the moving contact member 10 is moved to sequentially engage the fixed contacts 30 between the strips 12, 13. The fixed contacts 30 are capable of rotational adjustment about an axis 40 whilst the moving contact member is adjustable according to the degree of movement allowed by the gimbals 14. In another embodiment the moving contact member may comprise one strip only which may be received between two conductive surfaces spring urged together forming each of the fixed contacts. In a transformer tap changing system two such switches may be mounted on a common shaft with the rotors displaced by 180 degrees.