| 摘要 |
PURPOSE:To require no shielding and to make small size and a low price by connecting a nonlinear resistance made of mainly a metal oxide between windings in a transformer which has at least two windings wound concentrically around an iron core and the iron core. CONSTITUTION:A low voltage winding 3, a medium voltage winding 2 and a high voltage winding 1 are wound cylindrically around an iron core 4. Terminals U, (u) are provided in the high voltage and the medium voltage windings 1, 2 and a nonlinear resistance 5 wherein the main component is a metal oxide is connected nearly in the middle of the axial length of the cylindrical medium voltage winding 2, so to speak, nearly in the middle of the stack of the medium voltage winding 2, i.e., between a point (b) and the terminal U. This makes that the voltage of the insulation distance (MG) between the high voltage winding 1 and the medium voltage winding 2 is restrained by the limited voltage of the element 5 and overvoltage is not applied to between the MG. For this reason, the dimensions of the MG can be reduced and especially, the dimensions of the high voltage winding 1 can be reduced and a transformer can be miniaturized. |
