GB782264A - Improvements in or relating to current transformers - Google Patents

Abstract

782,264. Transformers. RITZ, H. Dec. 7, 1953, No. 34031/63. Class 38 (2). A current transformer has a secondary winding wound around a magnetic core such that the assembly has a disc-like form, the ends of the primary conductor terminating in flat surfaces on opposite sides of the disc so that the transformer can be inserted between two overlapping current leads-such as bus-barswithout the necessity for separate primary terminals, the primary connections being established in one operation with the mounting of the terminals. A secondary winding 2 is toroidally wound around a wound strip annular magnetic core 1, a current conducting tube 4 passing through the centre of the assembly and forming the primary winding so that the primary connections are made between the ends of the tube 4 and the bus-bars (shown dotted in Fig. 1) when the transformer, is secured between the bus-bars by means of a bolt 5. The transformer core and secondary winding assembly is housed in a casing of insulating material which casing may be in two parts 6a, 6b (see Fig. 2) and the secondary winding connections may be in the form of leads 3 or terminals 12 secured to the insulating casing. The two halves of the casing may be secured by an external circumferential spinning or by means of a hollow internal spinning 7 which may form the primary winding together with the tube 4. A number of embodiments aredescribed wherein the primary tube may be eccentric (see Fig. 21) or where the secondary winding may be eccentrically wound (see Fig. 24) or where the primary winding may be of the conventional wound type. Fig. 17 shows such a wound transformer where the magnetic core 27 has the secondary winding 28 and the primary winding 26 wound toroidally thereon, the ends of the primary winding 26 terminating in contact members 21, 22 spaced by a member 16 which may be of insulating material such as a ceramic or may be of a sintered magnetic material.