ל - רשר :
מתשובתך אני מבין כי אכן לא חובה לחבר את המגעים: 11 12 14 ( להלן מגעי הפיקוד אם אני מבין) על מנת שהמכשיר יגן מפני מתחי יתר . אשמח על תשובתך להערתי זו. כ"כ אני מצרף הסבר כללי ( באתר היצרן אין הסבר נוסף מעבר לתמונה שצירפתי בהודעתי המקורית בפורום - ראה תחילת השירשור.) How do we achieve protection against overvoltages? We have to consider overvoltage protection from two standpoints: General protective measures when designing and constructing the building and the electrical installations Special protective measures obtained by installing overvoltage protection components Designing the building and electrical installations Measures to protect against damage caused by overvoltages can be incorporated right at the start, when constructing a building and installing the electrical and electronic systems. Although this achieves only basic protection, it can help to reduce the cost of an effective overall protection concept. Very important right at the start of building work is the provision of an adequate earthing system. Only this can guarantee complete equipotential bonding in the case of an overvoltage event. When planning the electrical installations make sure that electrical equipment with different rated voltages are kept separate. Appropriate protection zones can then be set up and this reduces the costs of the overvoltage protection concept. Furthermore, it is advisable to shield lines that could interfere with each other, possibly also keeping them separate in order to achieve maximum electrical isolation. And splitting up the individual phases of three-phase systems according to functional supply requirements – e.g. just one phase for supplies to measuring and control equipment – is a good option. Of course, all these primary measures do not provide complete protection. To do that you need additional, overvoltage protection components. Overvoltage protection components To keep overvoltages away from electrical components that could be damaged by such voltages, they are short-circuited, i.e. forced to decay, before they reach the component. To do this we use arresters which react very quickly. They must respond during the high-frequency rise of the overvoltage – i.e. before a dangerous value is reached – and force the overvoltage to decay. The response time is in the region of nanoseconds. As a short-circuited overvoltage can reach several thousand amperes, depending on the energy source, it is obvious that overvoltage protection components must be able to handle very high currents. At the same time, – even if the operating current is very high – there must be no excessive, i.e. dangerous, residual voltages. Therefore, the discharge behaviour of overvoltage protection components must be based on a very low resistance. In addition, it is absolutely essential that after discharging an overvoltage to earth the overvoltage protection component is very quickly available again to continue protecting the circuits to which it is assigned. Good overvoltage protection is therefore characterised by: fast response behaviour high current-carrying capacity low residual voltage good reactivation time