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الموضوع: اسئلة عن ups لخبراء ups

  1. #1
    Junior Engineer
    تاريخ التسجيل
    Aug 2006
    الدولة
    Egypt
    المشاركات
    16

    اسئلة عن ups لخبراء ups

    السلام عليكم ورحمة الله وبركاتة
    اريد اجابة بعض الاسئلة عن ال ups والتى تواجهنى فى امتحان الدرسات العليا جزاكو الله عنى خيرا
    1- هل يتم اختيار ups طبقا لل kva او A hour ولماذا ؟
    2- هل يستخدم ال ups فى meduim voltage ولماذا ؟
    3- ما نوع ال harmonic الى يمكن ان تكون مطمئن لها بالنسبة لاشارة التيار الداخلة لل ups وكيف نتمكن من تقليلها ؟
    4- ما هى harmonics الموجودة فى موجة الجهد الخارجة ؟ وايضا بالنسبة للتيار ؟
    5- كيف يتم التعامل مع الharmonics فى تيار الخرج ؟ وكيف يتم التخلص منه نهائيا او يتم تخفيضه ؟ وفى حالة تخفيضه ما هو المستوى الذى يتم عنده التخفيض ؟
    6- كيف يتم استخدام ال chopper كا (step up or step down ) وكيف استخدامها فى bidirectional power flow ?
    7- كيف يستخدم current hysteresis للتحكم فى موجة تيار الداخله فى الconverter ؟ وكيف لها ان تجعل الجهد على مكثف التوحيد متذبذب ؟ وماهى مزايا هذه الطريقة ؟
    8- ما هو load depentent وما هو علاقته بعزل دخل وخرج ال ups ?
    9- ما هى انواع البطاريات المستخدمة فى ups وما هو الاختلاف بين كل منهن ؟

    ولكم جزيل الشكر منى
    ارجو المساعدة لاجتياز امتحان الدراسات العليا ولكم جزيل الشكر

  2. #2
    Junior Engineer الصورة الرمزية المهندس علي احمد مظلوم
    تاريخ التسجيل
    Jan 2007
    الدولة
    lebanon
    المشاركات
    6

    رد: اسئلة عن ups لخبراء ups

    1- هل يتم اختيار ups طبقا لل kva او A hour ولماذا ؟
    kva ,like generators sice the load have inductive and capacitive componnents,but thier a relation between the power (watt) and A hour
    2- هل يستخدم ال ups فى meduim voltage ولماذا ؟
    ups mostly installed for sensitive loads,thier no load in medium voltage
    3- ما نوع ال harmonic الى يمكن ان تكون مطمئن لها بالنسبة لاشارة التيار الداخلة لل ups وكيف نتمكن من تقليلها ؟

    4- ما هى harmonics الموجودة فى موجة الجهد الخارجة ؟ وايضا بالنسبة للتيار ؟
    5- كيف يتم التعامل مع الharmonics فى تيار الخرج ؟ وكيف يتم التخلص منه نهائيا او يتم تخفيضه ؟ وفى حالة تخفيضه ما هو المستوى الذى يتم عنده التخفيض ؟
    since the input of the ups have some times toomuch harmonics,we can filtered it by EMI boards
    6- كيف يتم استخدام ال chopper كا (step up or step down ) وكيف استخدامها فى bidirectional power flow ?
    chopper inside the inverter
    7- كيف يستخدم current hysteresis للتحكم فى موجة تيار الداخله فى الconverter ؟ وكيف لها ان تجعل الجهد على مكثف التوحيد متذبذب ؟ وماهى مزايا هذه الطريقة ؟
    8- ما هو load depentent وما هو علاقته بعزل دخل وخرج ال ups ?

    9- ما هى انواع البطاريات المستخدمة فى ups وما هو الاختلاف بين كل منهن ؟
    too much brand names ,but the different between them is the A hour

  3. #3
    Junior Engineer الصورة الرمزية Muhamed Vahid
    تاريخ التسجيل
    Jan 2006
    الدولة
    iraq
    المشاركات
    18

    رد: اسئلة عن ups لخبراء ups

    I am also interesting in it
    salam alikom

  4. #4
    عضو فى رابطة مهندسى الكهرباء العرب الصورة الرمزية osama gad
    تاريخ التسجيل
    Dec 2008
    الدولة
    6اكتوبر - الجيزة
    المشاركات
    156

    رد: اسئلة عن ups لخبراء ups

    An uninterruptible power supply (UPS), also known as a battery back-up, provides emergency power and, depending on the topology, line regulation as well to connected equipment by supplying power from a separate source when utility power is not available. It differs from an auxiliary or emergency power system or standby generator, which does not provide instant protection from a momentary power interruption. A UPS, however, can be used to provide uninterrupted power to equipment, typically for 5–15 minutes until an auxiliary power supply can be turned on, utility power restored, or equipment safely shut down.
    While not limited to safeguarding any particular type of equipment, a UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption or data loss. UPS units come in sizes ranging from units which will back up a single computer without monitor (around 200 VA) to units which will power entire data centers or buildings (several megawatts).
    كن كالنخيل عن الاحقاد مرتفعا
    يرمي بصخر فيلقي اطيب الثمر

    اعلم..... ان ما اصابك لم يكن ليخطأك ..... وما اخطأك لم يكن ليصيبك

  5. #5
    عضو فى رابطة مهندسى الكهرباء العرب الصورة الرمزية osama gad
    تاريخ التسجيل
    Dec 2008
    الدولة
    6اكتوبر - الجيزة
    المشاركات
    156

    رد: اسئلة عن ups لخبراء ups

    Offline / standby

    Offline / standby UPS. Typical protection time: 0 - 20 minutes. Capacity expansion: Usually not available


    The Offline / Standby UPS (SPS) offers only the most basic features, providing surge protection and battery backup. Usually the Standby UPS offers no battery capacity monitoring or self-test capability, making it the least reliable type of UPS since it could fail at any moment without warning. These are also the least expensive, selling for as little as US$40. The SPS may be worse than using nothing at all, because it gives the user a false sense of security of being assured protection that may not work when needed the most.
    With this type of UPS, a user's equipment is normally connected directly to incoming utility power with the same voltage transient clamping devices used in a common surge protected plug strip connected across the power line. When the incoming utility voltage falls below a predetermined level the SPS turns on its internal DC-AC inverter circuitry, which is powered from an internal storage battery. The SPS then mechanically switches the connected equipment on to its DC-AC inverter output. The switchover time is stated by most manufacturers as being less than 4 milliseconds, but typically can be as long as 25 milliseconds depending on the amount of time it takes the Standby UPS to detect the lost utility voltage.[]

    [Line-interactive


    Line-Interactive UPS. Typical protection time: 5 - 30 minutes. Capacity expansion: Several hours


    The Line-Interactive UPS is similar in operation to a Standby UPS, but with the addition of a multi-tap variable-voltage autotransformer. This is a special type of electrical transformer that can add or subtract powered coils of wire, thereby increasing or decreasing the magnetic field and the output voltage of the transformer.
    This type of UPS is able to tolerate continuous undervoltage brownouts and overvoltage surges without consuming the limited reserve battery power. It instead compensates by auto-selecting different power taps on the autotransformer. Changing the autotransformer tap can cause a very brief output power disruption, so the UPS may chirp for a moment, as it briefly switches to battery before changing the selected power tap.
    Autotransformers can be engineered to cover a wide range of varying input voltages, but this also increases the number of taps and the size, weight, complexity, and expense of the UPS. It is common for the autotransformer to only cover a range from about 90v to 140v for 120v power, and then switch to battery if the voltage goes much higher or lower than that range.
    In low-voltage conditions the UPS will use more current than normal so it may need a higher current circuit than a normal device. For example to power a 1000 watt device at 120 volts, the UPS will draw 8.32 amps. If a brownout occurs and the voltage drops to 100 volts, the UPS will draw 10 amps to compensate. This also works in reverse, so that in an overvoltage condition, the UPS will need fewer amps of current.


    [Double-conversion / online

    Typical protection time:5 – 30 minutesCapacity expansion:Several hours
    The Online UPS is ideal for environments where electrical isolation is necessary or for equipment that is very sensitive to power fluctuations. Although once previously reserved for very large installations of 10kW or more, advances in technology have permitted it to now be available as a common consumer device, supplying 500 watts or less. The Online UPS is generally more expensive but may be necessary when the power environment is "noisy" such as in industrial settings, for larger equipment loads like data centers, or when operation from an extended-run backup generator is necessary.
    The basic technology of the online UPS is the same as in a Standby or Line-Interactive UPS. However it typically costs much more, due to it having a much greater current AC-to-DC battery-charger/rectifier, and with the rectifier and inverter designed to run continuously with improved cooling systems. It is called a Double-Conversion UPS due to the rectifier directly driving the inverter, even when powered from normal AC current.
    In an Online UPS, the batteries are always connected to the inverter, so that no power transfer switches are necessary. When power loss occurs, the rectifier simply drops out of the circuit and the batteries keep the power steady and unchanged. When power is restored, the rectifier resumes carrying most of the load and begins charging the batteries, though the charging current may be limited to prevent the high-power rectifier from overheating the batteries and boiling off the electrolyte.
    The main advantage to the on-line UPS is its ability to provide an electrical firewall between the incoming utility power and sensitive electronic equipment. While the Standby and Line-Interactive UPS merely filter the input utility power, the Double-Conversion UPS provides a layer of insulation from power quality problems. It allows control of output voltage and frequency regardless of input voltage and frequency.

    [Hybrid Topology / Double Conversion on Demand

    Recently there have been hybrid topology UPSs hitting the marketplace. These hybrid designs do not have an official designation, although one name used by HP and Eaton is Double Conversion on Demand.[1] This style of UPS is targeted towards high efficiency applications while still maintaining the features and protection level offered by double conversion.
    A hybrid (double conversion on demand) UPS operates as an offline/standby UPS when power conditions are within a certain preset window. This allows the UPS to achieve very high efficiency ratings. When the power conditions fluctuate outside of the predefined windows, the UPS switches to online/double conversion operation.[2] In double conversion mode the UPS can adjust for voltage variations without having to use battery power, can filter out line noise and control frequency. Examples of this hybrid/double conversion on demand UPS design are the HP R8000, HP R12000, HP RP12000/3 and the Eaton BladeUPS.

    [Ferro-resonant

    Typical protection time:5 - 15 MinutesCapacity expansion:Several Hours
    Ferro-resonant units operate in the same way as a standby UPS unit with the exception that a ferro-resonant transformer is used to filter the output. This transformer is designed to hold energy long enough to cover the time between switching from line power to battery power and effectively eliminates the transfer time. Many ferro-resonant UPSs are 90-93% efficient and offer excellent isolation.
    This used to be the dominant type of UPS and is limited to around the 15KVA range. These units are still mainly used in some industrial settings due to the robust nature of the UPS. Many ferro-resonant UPSs utilizing controlled ferro technology may not interact with power-factor-correcting equipment.
    كن كالنخيل عن الاحقاد مرتفعا
    يرمي بصخر فيلقي اطيب الثمر

    اعلم..... ان ما اصابك لم يكن ليخطأك ..... وما اخطأك لم يكن ليصيبك

  6. #6
    عضو فى رابطة مهندسى الكهرباء العرب الصورة الرمزية osama gad
    تاريخ التسجيل
    Dec 2008
    الدولة
    6اكتوبر - الجيزة
    المشاركات
    156

    رد: التطبيقات

    Applications
    [edit] N+1
    In large business environments where reliability is of great importance, a single huge UPS can also be a single point of failure that can disrupt many other systems. To provide greater reliability, multiple smaller UPS modules and batteries can be integrated together to provide redundant power protection equivalent to one very large UPS. "N+1" means that If the load can be supplied by N modules, the installation will contain N+1 modules. In this way, failure of one module will not impact system operation
    [ Multiple redundancy
    Many computer servers offer the option of redundant power supplies, so that in the event of one power supply failing, one or more other power supplies are able to power the load. This is a critical point - each power supply must be able to power the entire server by itself.
    Redundancy is further enhanced by plugging each power supply into a circuit (i.e. to a different circuit breaker).
    While it is common practice by uninformed people to plug each of these individual power supplies into one single UPS, redundant protection can be extended further yet by connecting each power supply to its own UPS. This provides double protection from both a power supply failure and a UPS failure, so that continued operation is assured. This configuration is also referred to as 2N redundancy. If the budget does not allow for two identical UPS units then it is common practice to plug one power supply into mains power and the other into the UPS.
    [Outdoor use
    When a UPS system is placed outdoors, it should have some specific features that guarantee that it can tolerate weather with a 'minimal to none' effect on performance. Factors such as temperature, humidity, rain, and snow among others should be considered by the manufacturer when designing an outdoor UPS system. Operating temperature ranges for outdoor UPS systems could be around −40 °C to +55 °C.
    Outdoor UPS systems can be pole, ground (pedestal), or host mounted. Outdoor environment could mean extreme cold, in which case the outdoor UPS system should include a battery heater mat, or extreme heat, in which case the outdoor UPS system should include a fan system or an air conditioning system.
    [ Internal systems
    UPS systems can be designed to be placed inside a computer chassis. There are two types of Internal UPS. The first type is a miniaturized regular UPS that is made small enough to fit into a 5.25″ CD-ROM slot bay of a regular computer chassis. The other type are re-engineered switching power supplies that utilize dual power sources of AC and/or DC as power inputs and have an AC/DC built-in switching management control units.
    All these connections are connected to a common point called 'Earth'.
    [ Difficulties faced with generator use
    The voltage and frequency of the power produced by a generator depends on the engine speed. The speed is controlled by a system called a governor. Some governors are mechanical, some are electronic. The job of the governor is to keep the voltage and frequency constant, while the load on the generator changes. This may pose a problem where, for example, the startup surge of an elevator can cause short "blips" in the frequency of the generator or the output voltage, thus effecting all other devices powered by the generator. Many transmission sites will have backup diesel generators - in the case of AM, the load presented by the transmitters changes in line with the signal level. This leads to the scenario where the generator is constantly trying to correct the output voltage and frequency as the load changes.
    It is possible for a UPS unit to be incompatible with a generator or a poor mains supply; in the event that its designers had written the microprocessor code to require need exactly a 50.0Hz (or 60.0Hz) supply frequency in order to operate; with this condition not met the UPS could remain on battery power, being unable to reconnect the unsuitable supply voltage.
    This problem of input frequency requirements should not be an issue through the use of a Double Conversion / online UPS. A UPS of this topology should be able to adapt to any input frequency, using its own internal clock source to generate the required 50 or 60Hz supply frequency.
    A problem in the combination of a "double conversion" UPS and a generator is the voltage distortion created by the UPS. The input of a double conversion UPS is essentially a big rectifier. The current drawn by the UPS is non-sinusoidal. This causes the voltage from the generator also to become non-sinusoidal. The voltage distortion then can cause problems in all electrical equipment connected to the generator, including the UPS itself! This level of "noise" is measured as a percentage of "Total Harmonic Distortion of the current" (THD(i)). Classic UPS rectifiers have a THD(i) level of around 25-30%. To prevent voltage distortion, this requires generators more than twice as big as the UPS.
    There are several solutions to reduce the THD(i) in a double conversion UPS: Classic solutions such as passive filters reduce THD(i) to 5-10% at full load. They are reliable, but big and only work at full load, and present their own problems when used in tandem with generators. An alternative solution is an active filter. Through the use of such a device, THD(i) can drop to 5% over the full power range. The newest technology in double conversion UPS units is a rectifier that doesn't use classic rectifier components (Thyristors and Diodes) but high frequency components (IGBTs). A double conversion UPS with an IGBT rectifier can have a THD(i) as small as 2%. This completely eliminates the need to oversize the generator (and transformers), without additional filters, investment cost, losses, or space.
    واخيرا للامانة العلمية :-
    منقول من
    [url]http://en.wikipedia.org/wiki/Uninterruptible_power_supply[/url]
    كن كالنخيل عن الاحقاد مرتفعا
    يرمي بصخر فيلقي اطيب الثمر

    اعلم..... ان ما اصابك لم يكن ليخطأك ..... وما اخطأك لم يكن ليصيبك

  7. #7
    Junior Engineer الصورة الرمزية مهندس احمد الحلبي
    تاريخ التسجيل
    Aug 2010
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    fayed
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    21

    رد: اسئلة عن ups لخبراء ups

    شكرا علي تلك المعلومات الرائعه اخي الكريم

  8. #8
    Junior Engineer الصورة الرمزية محمد مطيع
    تاريخ التسجيل
    Dec 2010
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    القاهرة
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    رد: اسئلة عن ups لخبراء ups

    جزاك الله خيرا
    وإذ أمكن تجميع المعلومات فى ملف واحد

  9. #9
    Junior Engineer
    تاريخ التسجيل
    Oct 2011
    الدولة
    cairo
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    9

    رد: اسئلة عن ups لخبراء ups

    سؤال : يوجد لدينا فى المصنع ADPOS UPS
    SERIAL NO. 6MMA20K00B
    ولا نعرف لة اى معلومات لان كتالوجة مش موجود
    ياريت اى حد يقدر يفدنى ويوفرلى اى معلومات عنة
    شكرا

  10. #10
    Junior Engineer الصورة الرمزية sandro abdelhafith
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    May 2010
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    الاردن
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    رد: اسئلة عن ups لخبراء ups

    هذا الجهاز الماني الجنسية و بأمكانك ان تجد الكاتالوجات من الموقع الخاص للجهاز:

    http://www.adpos-ups.de/en/products.html

    حيث انك تستطيع اختيار اي مودل من القائمة الموجودة على يسار الصفحة

    وهذا مثال على كاتالوج
    http://www.adpos-ups.de/uploads/pdf/...c_brochure.pdf

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