GB658297A - Improvements in or relating to electrical transformers - Google Patents

Abstract

658,297. Transformers. BENDIX AVIATION CORPORATION. Sept. 27, 1948, No. 25162. Convention date, Sept. 30, 1947. [Class 38 (ii)] A shielded current transformer primarily for use in investigating the operation of electrical ignition systems and which eliminates the effects of capacity components comprises a straight conductor 8 forming the primary winding supported in a casing 5 and terminating if required at outlet sockets to permit connection in the ignition system, a lamination 10 surrounding the conductor and carrying on one side the secondary winding 14 connected to an outlet socket 20, shielding being effected by either a discontinuous split metallic sleeve 11, e.g. a split sheath of steel, surrounding the periphery of the winding 14, or a single or two telescoping tubes 27 insulated from each other, surrounding the primary conductor 8. The sleeve, and, if necessary, the core and one end of the secondary winding may be connected by a lead 21 to the case 5, and thence to earth. The core may be split and preferably form two U-shaped parts either of flat laminations or formed by continuous wrapping of a sheet strip around a mandrel, cutting into two parts and securing by a strap and clamp. The casing may be filled with an insulating compound 26, such as polymerized cashew nut shell oil in which case a greased rod, in lieu of the conductor may be inserted prior to filling so that when removed a passage is provided for the conductor 8.