| 摘要 |
730,634. Lightning arresters. E.M.P. ELECTRIC, Ltd. Nov. 23, 1951 [Oct. 7, 1950], No. 24537/50. Drawings to Specification. Class 38 (4). A lightning arrester for a high voltage power line comprises a spark-gap in series with one or more non-linear resistance elements contained in an insulating housing and so selected as regards their resistance characteristics that the followup current after a discharge does not exceed 5 amps. peak and is terminated at the next voltage zero, whilst during a discharge the resistance of the elements falls to such a value that the voltage resulting from the flow of discharge current lies well below the insulation level of the line. The spark-gap may be a rod or like open air-gap, and there may be also an additional quench gap, which is either located in the resistor housing, or in a separate housing. The rod gap may be divided into two sections, one of which is open and unenclosed, whilst the other is provided with a shunt resistor ring adapted to carry current upon break-down of the gaps and held in a housing separate from the resistor housing. Alternatively, the spark gap may comprise an enclosed gap unit housed in common with, or separately from, the resistance elements, the housing being so designed that external leakage current under normal working conditions is less than 0.1 milli-amp. Specifications 730,709 and 730,710 are referred to. |
