| 摘要 |
PURPOSE: To provide a surge preventing device with good short circuit performance which withstands electric/thermal destruction without mechanical decomposition of this varistor block stacked body occurring, even if arc generated due to a failure of an internal varistor block. CONSTITUTION: This surge preventing device includes a stacked body of a plurality of cylindrical varistor blocks 10 of metal oxide, and they are disposed between two end electrodes 11, 12 within a long insulating casing 23 of silicon rubber or other polymer material. These varistor blocks and the electrodes are surrounded in the axial direction by compressing loops 15-17 of an insulating material so that a necessary contact pressure is given between the different elements 10, 11, 12 of this varistor block stacked body. This varistor block stacked body 10 and the compressing loops are surrounded in the radial direction by a burst preventing winding body 21 with an open part 22 being provided by which the pressure escapes when internal short circuit occurs in this surge preventing device. |
