GB944273A - Improvements in or relating to electrical current and voltage controlling devices - Google Patents

Abstract

944,273. Transformers. WAYNE KERR LABORATORIES Ltd. May 10, 1960 [May 12, 1959], No. 18031/63. Divided out of 944,272. Heading HIT. [Also in Division G1] An inductive device usable as a current or voltage controller is formed a helical or spiral conductive strip 60 of rectangular section with a groove (or rib) for guiding movable tapping bushes 62. The flat sides of adjacent turns may be separated by thin insulating strips to reduce flux leakage. Coupling between the winding turns may be increased by providing a split conductive cylinder 61 around the winding. Additionally, as described in Specification 944,272 turns of the winding may be connected to corresponding turns of the winding of an auxiliary transformer 71. The depth of the facing sides of adjacent turns of the strip and the distance between them may be so proportioned as to result in stray inductances and shunt capacitances having equal effects. The pair of connected spring mounted brushes 62 are carried slidably on the edge of a flat conductive plate 64 held by a conductive rod 65 which is connected to a fixed radial arm 67. A magnetic dust or ferrite core may be provided and the supply lead to the winding may be connected 10% or 20% from its ends.. The brush may be arranged outside the winding and the conductive split cylinder inside. The conductor may be wound in a spiral and associated with a radially split annular conductive disc member. An impedance measuring system incorporating the inductive device is described.