基礎(chǔ)防雷外文資料翻譯-全文預(yù)覽
【正文】 t will not trip MOVs, gas tube arrestors, or other transient protection devices. Knowing the behavior of an event prior to occurrence is every businessman39。 get off the high ground。 protect all valuable plugin devices such as process control instrumentation, puters, printers, fire alarms, data recording amp。s day, lightning rods conducted current away from buildings to earth. Lightning rods, now known as air terminals, are believed to send Streamers upward at varying distances and times according to shape, height and other factors. Different designs of air terminals may be employed according to different protection requirements. For example, the utility industry prefers overhead shielding wires for electrical substations. In some cases, no use whatsoever of air terminals is appropriate (example: munitions bunkers). Air terminals do not provide for safety to modern electronics within structures. Air terminal design may alter Streamer behavior. In equivalent efields, a blunt pointed rod is seen to behave differently than a sharp pointed rod. Faraday Cage and overhead shield designs produce yet other effects. Air terminal design and performance is a controversial and unresolved issue. Commercial claims of the elimination of lightning deserve a skeptical reception. Further research and testing is ongoing in order to understand more fully the behavior of various air terminals. Downconductors, Bonding and Shielding Downconductors should be installed in a safe manner through a known route, outside of the structure. They should not be painted, since this will increase impedance. Gradual bends (min. eight inch radius) should be adopted to avoid flashover problems. Building steel may be used in place of downconductors where practical as a beneficial part of the earth electrode subsystem. Bonding assures that all metal masses are at the same electrical potential. All metallic conductors entering structures (AC power, gas and water pipes, signal lines, HVAC ducting, conduits, railroad tracks, overhead bridge cranes, etc.) should be integrated electrically to the earth electrode subsystem. Connector bonding should be thermal, not mechanical. Mechanical bonds are subject to corrosion and physical damage. Frequent inspection and ohmic resistance measuring of pression and mechanical connectors is remended. Shielding is an additional line of defense against induced effects. It prevents the higher frequency electromagic noise from interfering with the desired signal. It is acplished by isolation of the signal wires from the source of noise. Grounding The grounding system must address low earth impedance as well as low resistance. A spectral study of lightning39。 11。 9。莫里斯， i， .，火箭引雷研究的重要資產(chǎn)，在行業(yè)的應(yīng)用，卷匯刊保護(hù)。 1992。 4。 2。因?yàn)殚W電可能超出每一個(gè)人的想象。不要在下雨的時(shí)候在室外打電話 。用戶應(yīng)提防過度依靠設(shè)備，因?yàn)檫@不是每次都可用的。 安裝電涌抑制器的最小的引線長度取決于各自的電氣面板。電壓鉗位器件可以處理極高峰值的浪涌，以及具有減少極快的上升沿瞬態(tài)的能力。地球的零電位是防雷接地最重要的原因。低頻率分量延續(xù)時(shí)間長，是一種高能量后
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