Patent ID: 8552737

Claim:
A high-voltage transformer ( 1 ) for supplying a.c. voltage in the kV range, with at least one secondary winding ( 12 ), which is wound on a coil support ( 11 ) surrounding a transformer core ( 2 ), comprising: an insulating housing ( 5 , 6 ) encapsulating the secondary winding ( 12 ) for electrical insulation of the secondary winding ( 12 ), which insulated housing is walled by the coil support ( 11 ) carrying the secondary winding ( 12 ) and by a shell structure ( 14 ) made of plastic and surrounding the secondary winding ( 12 ) while forming an annular gap ( 13 ), wherein the annular gap ( 13 ) between secondary winding ( 12 ) and shell structure ( 14 ) is filled with an insulating fluid, wherein the annular gap ( 13 ) filled with insulating fluid has a gap width of smaller than or equal to 20 mm considered in cross section, wherein the shell structure ( 14 ) has a wall thickness of smaller than or equal to 20 mm, wherein the plastic is polypropylene, and wherein no separate expansion volume is provided for the insulating fluid.