Oil-immersed electrical apparatus having oil-impregnated main insulation partly covered by liquid-impervious material

Claim 1

ELECTRICAL APPARATUS OF THE KIND WHICH IS IMMERSED IN OIL COMPRISING A PLURAITY OF ELECTRICAL CONDUCTORS WHICH IN USE ARE OF DIFFERENT POTENTIALS AND ADJACENT TO ONE ANOTHER AND ARE CLOSELY WOUND TO FORM A COIL HAVING TWO MAIN SURFACES IN CONTACT WITH THE OIL, EACH CONDUCTOR BEING COVERED BY A MAIN INSULATING COVERING OF A MATERIAL WHICH IN USE IS IMPREGNATED BY THE OIL AND EACH CONDUCTOR FURTHER HAVING AN INSULATING PART-COVERING OF A MATERIAL WHICH IS IMPERVIOUS TO LIQUIDS, THE PART-COVERING SURROUNDING AND PARTLY BUT WHOLLY COVERING THE MAIN INSULATING COVERING SO AS TO ALLOW THE IMPREGNATION OF THE MAIN INSULATING COVERING WITH INSULATING OIL BUT TO RESTRICT THE ABSORPTION OF WATER BY SAID MAIN COVERING AND WHEREIN THE INSULATING PART-COVERING OF ALTERNATE CONDUCTORS IS DISPOSED AROUND THAT PORTION OF THE CONDUCTOR WHICH FORMS PART OF ONE OF SAID MAIN SURFACES AND THE INSULATING PART-COVERING OF THE INTERMEDIATE CONDUCTORS IN DISPOSED AROUND THAT PORTION OF THE CONDUCTOR WHICH FORMS PART OF THE OTHER MAIN SURFACE.