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الموضوع: Surge Protection

  1. #1
    عضو فى رابطة مهندسى الكهرباء العرب الصورة الرمزية بندراوي
    تاريخ التسجيل
    May 2006
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    862

    Surge Protection

    السلام عليكم ورحمة الله وبركاته
    A surge protector is basically a device that keeps power levels constant against power line fluctuations. This is different from the power supply which converts the line AC power to DC power the computer and other equipment require to operate.

    If a surge protector is not used, fluctuations in the power line can, potentially, have drastic effects on the computer. It can lock up, data can be corrupted, or, in the extreme, components can fry. There are several power problems that must be protected against...

    Brownout. A reduction in line voltage. In the U.S. the standard is 120 volts. During a brownout this can go down as low as 88 volts. A brownout can be a very short event or, in the case of overall power demand exceeding supply, a very long event.
    Surge. Basically, the opposite of a brownout: a temporary increase in voltage.
    Spike. As the name implies, a spike is a major event that lasts only a very short time. The most common causes of spikes are nearby lightning strikes and the spike that occurs when power which has been off comes back on.
    Noise. Basically, any sort of electromagnetic interference which impresses itself on the power system.
    Blackout. The ultimate brownout; a complete loss of power.
    A good surge protector can provide some protection against everything above except long brownouts or a blackout. For those you will require an uninterruptible power supply (UPS).

    When studying various models of surge suppressors consider these factors...

    Underwriter Laboratories Standards. If you care to study it the UL standard that applies is UL 1449. The clamping levels allowed in the standard are 330, 400, and 500 volts. Pick a model with the lowest level (330V) as the power supply might not be able to handle the higher levels.
    Energy Absorption in Joules. The higher the better here (try for 600 at least).
    Response Time. The shorter the better here. Surge devices take time to respond and the longer the time taken the more chance there will be for damage to the equipment. We're taking very short times here. Response time should be no longer than one nanosecond (billionths of a second) and it's better if they are in the picosecond (trillionths of a second) range.
    Circuit Breaker. The electronic circuits in the surge protector are not themselves immune to spikes. If a large enough spike comes along the surge protector can, itself, fry. Thus, a circuit breaker should be a required part of a surge protector.
    Line Conditioning. Some form of line conditioning should be considered for any surge protector. The power company usually does a good job of this but problems can be imposed on the line in transit.
    Health Indicators. The main component of a surge protector is a ****l oxide varistor (MOV). A MOV will, over time, eventually go bad as it is repeatedly stressed. A good surge protector will have an indicator of some sort (usually an LED) that tells you if the MOV is still good. If an MOV goes bad the surge protector is nothing more than an extension cord.
    Guarantee. A good surge protector will have a guarantee that says the company will replace not only a protector that does not protect but any connected equipment that is harmed. While it's not exactly comforting to have equipment damaged; getting it replaced helps a little.
    Modem Connection. It's not uncommon to protect a computer and monitor but forget that other devices are connected to the computer. Having protection for a printer is fairly obvious but many people forget that the modem is also a source of problems through the phone line. A surge that comes down the phone line (e.g., nearby lightning strike) can fry your computer through the modem connection. Thus, the phone line should also be protected.
    Network Connection. For reasons similar to those describe just above for a modem all network connections should also be protected.
    Ground Fault Indicator. A good surge protector will also have ground fault indication built into it. Should your power line grounds be bad it's possible to get electrical shocks from improperly-grounded equipment. An indicator on the surge protector can tell you this and should be considered important.
    Finally, be certain to find out if the surge protector actually protects when its power switch is in the off position. Let that be your guide as to using the protector's switch as your computer's master switch.

  2. #2
    Junior Engineer الصورة الرمزية نجيب سعد
    تاريخ التسجيل
    Oct 2006
    الدولة
    اليمن
    المشاركات
    63

    رد: Surge Protection

    شكراً

  3. #3
    Junior Engineer الصورة الرمزية محمد ممدوح
    تاريخ التسجيل
    Dec 2006
    الدولة
    egypt
    المشاركات
    27

    رد: Surge Protection

    جزاك الله خيرا

  4. #4
    V.I.P Member
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    Sep 2007
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    رد: Surge Protection

    بارك الله فيك

  5. #5
    V.I.P Member الصورة الرمزية محمد حسن السيد
    تاريخ التسجيل
    May 2006
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    رد: Surge Protection

    شكرا لك اخى الكريم ولى سؤال كيف اعمل حمايه كامله لمبنى من الصواعق ارى بعض الشركات تضع على حدود المبنى العلويه شريط من الباس بار متصل سؤالى كيف يتم اختيار الحسابات الخاصه بهذا النوع من الحمايه وكيف يتم تحديد القياسات المطلوبه طبقا للمبنى وعلى اى اساس ارجو الاجابه بالعربيه

  6. #6
    Junior Engineer الصورة الرمزية محمد حافظ
    تاريخ التسجيل
    Feb 2007
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    مصر
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    32

    رد: Surge Protection

    جزاكم اللة خيرا

  7. #7
    Junior Engineer الصورة الرمزية م/أحمد عطايا
    تاريخ التسجيل
    Apr 2006
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    المدينة المنورة
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    رد: Surge Protection

    مشكور كتير أخى الكريم وانشاء الله تمدنا دايما بهايك مواضيع مهمه

  8. #8
    عضو فى رابطة مهندسى الكهرباء العرب الصورة الرمزية احمد محمد عبد النبى
    تاريخ التسجيل
    Sep 2006
    الدولة
    Alex-Egypt
    المشاركات
    298

    رد: Surge Protection

    جزاكم الله الف خير
    اسئلكم الدعاء لى والمسلمين بالهداية والصلاح



  9. #9
    Junior Engineer الصورة الرمزية shady mosa
    تاريخ التسجيل
    Oct 2006
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    Dubai
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    81

    رد: Surge Protection

    مشكور أخى الكريم
    shadyshady

  10. #10
    V.I.P Member الصورة الرمزية محمد محمود داوود
    تاريخ التسجيل
    Jul 2007
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    رد: Surge Protection

    جزاك الله خيرا

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