GB1432212A - Transformers - Google Patents

Abstract

1432212 Transformers ALLMANNA SVENSKA ELEKTRISKA AB 29 Aug 1973 [30 Aug 1972] 40668/73 Heading HIT At least one of the windings of a transformer, supported on at least one magnetic core 9, is enclosed in a sealed case comprising at least two hollow parts 1, 2 of insulative material having their surfaces coated with electrically conductive layers, the parts being joined after assmbly to form a closed container. Preferably the electrically conductive layers are applied by a metallizing process directly to the surfaces of casing parts made of cast plastics, being excluded from the mating edge surfaces of the parts. In a current transformer Fig. 2, a secondary 11 wound on annular cores 9 is enclosed in a case in the form of a hollow annulus having a pipe 13 to carry the secondary terminal conductors 12. A primary winding 15 may be wound around the casing through the central channel 6 and provided with terminals 16; or the primary may simply comprise a single conductor passing through the channel 6. The transformer may be enclosed in conductive or insulative protective cover 18 mounted on a hollow insulator 17. The conductive layer lining the annular cavity 8 is kept at substantially the secondary winding potential, and the layer on the outer surface of the case is kept at the primary potential. An isolating voltage transformer may be similarly constructed.