GB883855A - Electrical inductive apparatus - Google Patents

Abstract

883,855. Electric transformers. WESTING- HOUSE ELECTRIC CORPORATION. Feb. 8, 1960 [Feb. 16, 1959], No. 4320/60. Class 38 (2). In a transformer having its primary and secondary windings formed of conducting sheet material and with the secondary turns interleaved with some of the primary turns as described in Specification 872,073, a device such as a current transformer, a reactor, a saturable reactor or other non-linear impedance is arranged to vary the potential between the interleaved primary and secondary windings with variation of load current. Fig. 2 shows a current transformer 80 connected to increase the potential across the dielectric insulation between primary turns 30B and secondary turns 60 as the load current increases so that the leading current taken by the inherent interwinding capacity 72 is increased. The primary winding of transformer 80 may be connected to the mid-point of 60 instead of to terminal 86. The interwound part of the primary winding may begin with the first inner turn. Instead of a current transformer a reactor 88 (Fig. 4) connected in the primary lead to terminal 102 may be provided. Alternatively a saturable reactor 94 (Fig. 3) may be used, the saturation of the core, like the saturation of the current transformer core referred to above, limiting the effect of overload in the main circuits. In another embodiment the variation of potential with load current is obtained by connecting a thermistor between the terminals 86 and 116 the impedance of the thermistor varying with the temperature of e.g. the insulating oil which in turn varies with the load current.