L.S.P. E

6/28

GGGgroundingsignallinesystempowerlinesurgeprotector6Entry pathway of lightning surgeDue to the online application of modern electronic systems, there are multiple interfacing parts to the outside for an instrument. One of such interface parts is signal cable and the other one is power cable. These cables pulled from the outside can be perfect entry pathways for the lightning surge.The effects of induced surge on a connected device will be more severe when the connected cable is longer and the device is located closer to the place where the actual lightning strikes. Even lightning rods with minimal cable length do not al-ways protect as they are hoped.The effect of lightning surges depends upon the cable location and its environ-ment. Surge protectors installed in those paths absorb and eliminate the high volt-age impulse energy and protect the electric instrument from damage (Figure 5-1).Breaking mode of electrical instrumentSurge voltage generated between a cable and the ground might reach several tens of thousands of volt, however, lightning occurs at a voltage typically five thousand volts between the cable and the ground, while it induces several hundred volts between lines.When analyzing breaking condition of the instrument, it is often broken by this line voltage. We call it ʻinterline breakdownʼ. Characteristics of interline breakdown is that semiconductor parts near the entry point of lightning surge breaks.Also, breaking mode between the cable and the ground is called ʻdischarge breakdownʼ. Because the lightning surge voltage is very high against that of the ground, an arc discharge is generated between an electronic circuit and a grounded enclosure. Characteristics of discharge breakdown is that weak part of insulation between the circuit and enclosure breaks down.M-Systemʼs surge protectors keep the surge voltage level at which instrument does not get damaged and prevent interline breakdown and discharge breakdown.Interline breakdown (V1)This occurs when the surge voltage between cables is directly applied to the electronic components in the instrument. Usually, only these components that are located near the termination of the cable where the surge entered are destroyed.Figure 5-1

※このページを正しく表示するにはFlashPlayer10.2以上が必要です