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Transformer變壓器 One of the most valuable apparatus in electric power system is the transformer, for it enables us to utilize different voltage levels across the system for the most economical value. Generation of power at the synchronous machine level is normally at a relatively low voltage, which is most desirable economically Stepping up of this generated voltage to high voltage, extra-high voltage or even to ultra-high voltage is done through power transformers to suit the power transmission requirement to minimize losses and increase the transmission capacity of the lines This transmission voltage level is then stepped down in many stages for distribution and utilization purposes 電力系統(tǒng)中的最有價值之一是器具的變壓器,它使我們能夠利用不同電壓等級,整個系統(tǒng)的最經(jīng)濟的值。通常在較低功率在同步計算機級別的一代是 voltage , which ,是最理想的 economically Stepping 高 voltage, extra 高電壓該生成電壓或甚至超高電壓通過以適應(yīng)電力傳輸?shù)囊?,盡量減少損失的電力變壓器和增加 lines This 輸電電壓等級的輸電量然后走在很多階段的分布和利用的目的 最有價值的一個裝置在電力 系統(tǒng)變壓器 ,因為它使我們能夠利用不同系統(tǒng)電壓水平在最經(jīng)濟的價值。一代的電力水平同步機通常以較低的電壓 ,這是最理想的 economically.Stepping 這產(chǎn)生電壓高壓、超高壓甚至是通過高壓電源變壓器適應(yīng)電力傳動要求減少損 失 ,提高傳輸容量的lines.This 傳輸電壓水平就下來了許多階段 ,分配和使用目的。 A transformer is a static device for transferring electric energy from one circuit to another electromagnetically, that is, by induction instead of by conduction Its usual function is to transfer energy between circuits of different voltage A transformer has a magnetic core on which there are two or more windings These windings are insulated from each other and from ground In autotransformers, however, the windings are connected together The assembly of core and coils is normally insulated and cooled by immersion in mineral oil or other suitable liquid within an enclosing tank Connection to the windings is by means of insulating bushings, usually through the cover. 變壓器是一個靜態(tài)的裝置電能量轉(zhuǎn)移到另一個排列從一個電路 ,通過誘導而不是conduction.Its 通常以換乘功 能電路 voltage.A 間能量不同變壓器磁芯上有一個有兩個或兩個以上繞組 windings.These 彼此隔離和 ground.In autotransformers,然而 ,繞組連接組裝的核心和線圈手工相結(jié)合 ,通常是由沉浸在保溫和冷卻液礦物油或其他適合在一個附上的tank.Connection 繞組通過絕緣襯套 ,通常是通過封面。 變壓器是核心的將電能從一個電路轉(zhuǎn)移到另一個 electromagnetically, that is, by 感應(yīng)而不是核心的,由 conduction Its 常用函數(shù)的靜態(tài)裝置是核心的 不同的 voltage A 變壓器電路之間傳輸能量已磁芯的有兩個或更多的 windings These 繞組彼此隔離從 ground In autotransformers, however, the 繞組連接的 together The 大會和是核心的線圈通常是核心的絕緣和冷浸于礦物油中或其他合適的液體內(nèi)封閉 tank Connection 在繞組絕緣蓋通過 bushings, usually 的手段。 The “ratio of transformation” is determined by the relative number of turns in each of he windings This is known as the “turn ratio” and it is the ratio of the no-load voltages When the unit is carrying load, the ratio of the actual voltages is slightly different because of the drop caused by the flow of 1oad current through the impedance of the transformer windings At rated load, this drop is known as the voltage regulation. The amount of voltage drop varies with the power factor of the output even when the kilovolt-amperes remain constant Practically all power transformers and many distribution transformers have taps in one or more windings for changing the turn ratio Changing the ratio is desirable for two reasons to compensate for varying voltage drop in the system and to assure that the transformer operates as nearly as possible at the correct core density For the latter purpose, the taps should be in the winding subject to the voltage variation. De-energized tap changers are used when it is expected that the ratio will need to be changed only infrequently, because of load growth or some seasonal change The desired tap is selected by means of a ratio adjuster(no load taps) Load tap changer(LTC)is used when changes in ratio may be frequent or when it is undesirable to de-energize the transformer to change a tap It seldom makes much difference to the user which winding or windings are tapped; therefore, the choice is usually made by the designer on the basis of cost and good design. Both winding current and voltage must be considered when applying LTC equipment High voltage and high current applications require special considerations to arrive at an optimum location for the LTC equipment Step down units usually have LTC in the low-voltage winding and de-energized taps in the high voltage winding 轉(zhuǎn)型的比率 是由他每圈相 對數(shù)決定的 windings This 稱為 轉(zhuǎn)率 ,這是空載 voltages When 股的比例承載負荷,因為下降 1oad 通過的阻抗變壓器 windings At 額定負載電流的流動引起的實際電壓的比例略有不同這滴被稱為 電壓調(diào)節(jié) 。即使當千伏安培保持所有電源變壓器和許多配電變壓器有水龍頭的一個或多個繞組更改比率是可取的原因有兩個補償系統(tǒng)中變電壓降,并向保證變壓器操作正確核心 density For,后者的目的在盡可能接近的轉(zhuǎn) ratio Changing constant Practically 的電壓降量隨輸出的功率因素水龍頭應(yīng)在電壓變清盤。切斷調(diào)壓分接開關(guān)時預(yù)期比例將需要更改只有很少,因為負荷增長的使用或一些季節(jié)性的 change The 需要選擇了水龍頭比調(diào)節(jié)器 (無負荷水龍頭) 的方式時比率的更改可能會頻繁 , 而使用 Load 分接開關(guān) ( LTC) 時,是不可取 de-energize 更改很少 tap It 變壓器多大差別,用戶或其中纏繞或繞組用 tapped;therefore, the 選擇通常是由設(shè)計器成本和好的設(shè)計的基礎(chǔ)上作出的。繞組電流和電壓必須考慮當應(yīng)用 LTC equipment High 電壓和高當前的應(yīng)用程序需要特殊的注意事項,到達最佳位置為單位下來 LTC equipment Step 通常會 LTC 中低壓繞組和斷電絲錐在高電壓 winding “比轉(zhuǎn)變”是由相關(guān)的圈數(shù)他 windings.This 在每個被稱為“轉(zhuǎn)比率”以及它是空的比例 voltages.When單位帶負荷、糧經(jīng)比實際電壓下降的略有不同 ,因為造成 1 oad流動的電流通過阻抗變壓器的額定載荷的 windings.At,這滴被稱為“電壓調(diào)節(jié)”。電壓降的數(shù)量隨輸出的功率因數(shù)即使 kilovolt-amperes保 持不變。 幾乎所有開關(guān)電源變壓器、配電變壓器有許多水龍頭在一個或多個線圈來改變這一比例將 ratio.Changing 是可取的 ,有兩個原因來補償系統(tǒng)中不同電壓降 ,以確保變壓器運行正像可能正確的核心 density.For后者目的、水龍頭應(yīng)該在繞組的電壓變化主題。不帶電更換時用自來水預(yù)計比例將需要改變 ,只是偶爾 ,因為負荷增長或一些季節(jié)性選擇所需的龍頭 ;通過比例調(diào)節(jié)器 (無負荷水龍頭 ).Load 分流器(等 ),是用來改變時可以在比頻繁或心甘情愿地德活力變壓器以改變一個 tap.It 很少會造成大的差別用戶繞組卷繞或輕 ,所以 ,選擇是通常由設(shè)計師基礎(chǔ)上的成本和好的設(shè)計。兩個繞組電流和電壓時必須考慮應(yīng)用等 equipment.High電壓和大電流應(yīng)用需要特別考慮到一個最佳位置 ,為等 equipment.Step 單位通常有療效下在低壓線圈繞組和不帶電水龍頭在高壓繞組。 When energy is to be transferred between two circuits of nearly the same voltage The use of autotransformers affords cost savings over two-winding units The nearer the voltages are to each other, the smaller will be the autotransformer per kilovolt-ampere of output, and the greater the savings The simplicity of phasing out systems has increased its use Most autotransformers are Y-connected, and it has been a standard American practice to add a low capacity, delta winding This is frequently referred to as a “delta tertiary“ Its primary purpose has been to provide an internal path for the third harmonic currents (required for excitation), thus reducing those currents on the power system It also helps to stabilize the neutral and to ground the system better In recent years, the use of shielded telephone cable has reduced the requirements for the delta tertiary. Because an autotransformer does not afford electrical separation between the two circuits, disturbances originating on one circuit can be communicated to the other This difficulty is minimized by solidly grounding the neutral of the autotransformer. Solidly grounding the neutral , however, causes(among other things)current of short-circuit magnitude to flow through the delta-connected tertiary winding during ground faults on either system. Autotransformers are not inherently self-protecting and, therefore, all windings must be examined for mechanical strength as applied to the system where they will be used . Tertiaries are normally 35 of the physical size of the largest winding of the autotransformer, unless otherwise specified by the user. 當能量將會轉(zhuǎn)移到在兩個電路 voltage.The 幾乎一模一樣的使用提供了autotransformers 節(jié)約成 本 two-winding units.The 離電壓是對方 ,較小的將是每kilovolt-ampere autotransformer 輸出 ,越簡單的 savings.The 淘汰系統(tǒng)是提高autotransformers 四 use.Most,這是個標準的美國做法添加一個低容量、三角洲winding.This經(jīng)常被稱為一個“增量高等教育“牽引 ,主要目的是提供一個內(nèi)部路徑為第三諧波電流 (要求勵磁 ),從而減少那些電流電源系統(tǒng) ,也有助于穩(wěn)定中性及地面系統(tǒng) better.In近年來 ,使用屏蔽電話電纜具有降低了要求高等職業(yè)學校教 育。伊洛瓦底三角洲因為一個 autotransformer不負擔兩個電路電氣脫節(jié)、干擾來源于一個電路能溝通的困難是減少工序的扎實的 autotransformer接地中立。堅定接地中性的 ,然而 ,使 (還有其他的議題 )短路電流的大小 delta-connected 流到地面故障時 ,在第三繞組或系統(tǒng)。 Autotransformers并非內(nèi)在自我 ,因此必須查看所有繞組機械強度作為應(yīng)用系統(tǒng)在哪里他們將被用到。 Tertiaries通常是 35%的物理尺寸最大的繞組中的 autotransformer,除另有規(guī)定外 ,由用戶。 當能 量是兩個幾乎相同 voltage The 使用的耦電路之間傳輸提供節(jié)省成本超過雙繞組 units The 靠近,電壓是彼此,就越小自耦變壓器每千伏安培的較大的 output, and savings The 簡單的逐步淘汰系統(tǒng)增加了其 use Most 耦是 Y connected, and 已添加低容量的標準美國實踐 winding This 通常稱為 三角專上 Its 的主要目的已提供內(nèi)部路徑 (需要勵磁) 的第三個諧波電流, thus 減少這些電源 system It 上的電流也有助于穩(wěn)定中性和地面的系統(tǒng) better In 最近 years, the 使用屏蔽電話電纜的三角洲減少了高等教育的三角洲的要求。因為自耦變壓器不起兩個電路之間的電分離,可以傳達一個電路上原產(chǎn)的擾動,other This,困難最小化通過扎扎實實地接地的自耦變壓器中性。扎扎實實地接地 neutral, however,原因 (除其他外) 電流的短路三角洲連接專上纏繞在任一系統(tǒng)接地故障期間內(nèi)流動的嚴重程度。耦本來就不 self-protecting 和 therefore, all 繞組必須審查的機械強度,適用于使用場合的系統(tǒng)。 Tertiaries 通常是 35 of 的物理大小的最大清的自耦變壓器,除非另有指定的用戶。 The bulk of a11 transformers, except for large extra-high voltage(EHV)and distribution units are three-phase units In the early days of the industry, It was almost universal practice in the United States to use three single-phase units connected in a three-phase bank Insulation clearances and shipping limitations for certain large EHV units now require this design The distribution systems serve mainly single-phase loads in residential areas and are served from single-phase transformers 大部分的大型超高壓 (超高壓) 和配電設(shè)備是在早期工業(yè)的三相 units 是在美國使用連接三相 bank Insulation 間隙中的三個單相單位幾乎普遍做法和運輸條件的某些大型超高壓單位現(xiàn)在需要此 design The 分布系統(tǒng)服務(wù)主要是單相負荷在住宅區(qū)和服務(wù)的單相 transformers a11 transformers, except 各式各樣的變壓器的體積 ,除了大型超高壓 (超高壓 )、銷售單位三相單位。在早期的產(chǎn)業(yè) ,它幾乎是普遍的實踐在美國使用三個單相單 位連接在一個三相bank.Insulation 間隙和運輸限制某些大型超高壓單位現(xiàn)在需要這個設(shè)計為單相負荷分配系統(tǒng)的主要在居民區(qū)和供應(yīng)從單相變壓器。 Selection and Cooling of Power Transformer 選擇和冷卻的電力變壓器 選擇與電力變壓器冷卻 The selection of the transformer can have a major impact on the cost a substation, since the transformer represents the major cost item Nameplate rating is only a guide to transformer application, and should only be used as a first step in the selection process. The transformer is available as a self-cooled unit, or it can be purchased with additional steps of forced cooling that use fan or fans and oil pumps Transformer ratings can be increased from 25 to 66 by the addition of fans and pumps The nameplate rating is based on a continuous load producing a 55 to 65 conductor temperature rise over ambient. Since many transformers do not carry continuous loads, advantage can be gained from the thermal time lag to carry higher peak loads without exceeding the temperature limits .Transformer ratings are based on the assumption that only an extremely slow deterioration of insulation will take place with normal operation A substantial increase in rating can be achieved by accelerating the loss of insulation life This increase in rating might approach 200for an hour or two, and approximately 120 for 24 hours For substations that are designed to carry full load under the outage of any one transformer, a high emergency rating for a 24-hour period (e.g. until the failed unit can be replaced) could mean the selection of smaller transformers and a substantial saving in substation cost The selection of the transformer should involve a careful evaluation of a number of other factors: 變壓器的選擇帶來了極大的負面影響一個變電站的成本 ,因為變壓器代表主要成本 item.Nameplate評級是唯一指南在變壓器應(yīng)用 ,只應(yīng)作為第一步選擇過程。變壓器是可作為一個 self-cooled 單位 ,也可以購買額外的步驟 ,使用強迫冷卻風扇或球迷和石油 pumps.Transformer 評級可以從 25%上升到 66%增加的球迷和水泵銘牌評級是基于一個持續(xù)負荷 55生產(chǎn)到 65環(huán)境溫度上升的導體。由于許多變壓器不帶連續(xù)荷載 ,可以得到優(yōu)勢進行熱滯后時間沒有超過峰值負荷較高的溫度范圍。變壓器評級建立在假定只有一個極慢的惡化將發(fā)生與普通保溫措施大幅度增加評級可以達到加速損失的絕緣 life.This 評級可能已經(jīng)接近 200%增加一兩個小時 ,而大約有 120%,24 hours.For變電站用于承受負荷的任何一個變壓器的中斷 ,高緊急等級來 24小時內(nèi) (例如 ,直到失敗單元可以代替 )可能意味著選擇較小的變壓器以及大幅度節(jié)省變電站成本。 變 壓器的選擇應(yīng)該包括仔細評估其他一些因素 : 變壓器的選擇可以在成本上,變壓器代表成本 item Nameplate 評級的主要是不僅指南變壓器 application, and 只用于作為第一步選擇過程中的 substation, since 產(chǎn)生重大影響。變壓器是可用的因為自冷的 unit, or,它可以購買的強制冷卻使用風扇或風扇和油 pumps Transformer 評級的額外步驟可以從 25 由增加到 66 的球迷和 pumps The 銘牌評級基于對環(huán)境產(chǎn)生 55 至 65 導體溫升連 續(xù)負載。由于許多變壓器不帶連續(xù) loads, advantage 可以獲得熱滯后時間不超過溫度限制的情況下進行更高的峰值負載。變壓器評級基于假設(shè)只有極其緩慢惡化的絕緣的進行大量正常 operation A 評級的增加可以實現(xiàn)通過加速的絕緣 life This 增加評級中的損失可能接近每小時 200 for 或兩個和約 120 for 24 hours For 變電站,為了把滿負載下的任何一個變壓器停電緊急高評級的 24 小時內(nèi) (例如直到失敗可以更換設(shè)備) 可能意味著更小的變壓器的選擇,并大幅度的變壓器選擇保 存在變電站花費了。 應(yīng)涉及慎重評估的一些其他因素是 : (1)Impedances should be selected considering their effect on short-circuit duties and low-side breaker ratings both for initial and future station developments In addition, impedance is important to achieve a proper load division in the parallel operation of transformers. (2)No load tap ranges should be selected to provide an adequate low-side bus voltage. (3)If the high-side or low-side voltages vary over a wide range during the load cycle, it may be necessary to provide bus regulation The actual regulation can be calculated using the system and load characteristics If regulating equipment is needed, it may be desirable to provide it in the transformer by using load tap changer(LTC) equipment. If the need for bus regulation is not presently evident, but may be required in the future, it may be economical to leave space in the station for future regulators, and buy transformers without LTC equipment. (1)阻抗選擇應(yīng)考慮他們的職責和 low-side 影響斷路器評分短路的初始和未來都站 developments.In。此外 ,阻抗是很重要的 ,取得適當?shù)钠叫凶鳂I(yè)負荷的分裂變壓器的 . . (2)不負載范圍應(yīng)選擇水龍頭提供適當?shù)?low-side母線電壓。 (3)如果高端或 low-side 電壓范圍在不同載荷循環(huán)期間 ,可能有必要提供汽車regulation.The 實際規(guī)定可以計算系統(tǒng)和負載 characteristics.If 調(diào)節(jié)設(shè)備是必需的 ,它可能需要它提供在變壓器采用負載分流器 (等 )設(shè)備。如果需要汽車目前規(guī)定不明顯 ,但可能需要在未來 ,它可能是經(jīng)濟在車站離開空間為未來的管理者 ,而且買變壓器等設(shè)備沒有。 () 1 考慮到對他們影響短路職責和低邊斷路器評級最初和未來站 developments In addition, impedance 是重要實現(xiàn)的變壓器并聯(lián)運行一個恰當?shù)呢撦d司應(yīng)選擇阻抗。 ( 2) 應(yīng)提供足夠低邊母線電壓選擇沒有加載水龍頭范圍。 () 3如果高邊或偏低電壓隨負載周期期間的范圍廣泛,可能需要提供可以使用系統(tǒng)計算巴士 regulation The 實際監(jiān)管和調(diào)節(jié)設(shè)備的負載 characteristics If 是 needed, it 可能需要通過使用負載水龍頭 changer(LTC) 設(shè)備提供它的變壓器。如果總線管需要不是目前是顯而易見的但可能需要在未來,它可能為將來的監(jiān)管者,站在離開空間,買不需 LTC 設(shè)備變壓器經(jīng)濟。 A great many transformers, including all the large ones and all the high voltage ones are immersed in mineral oil which serves the double purpose of cooling and insulating the windings. Small transformers have enough tank surface to radiate a11 the heat caused by their losses without exceeding the permissible temperature rise As size increases, the losses increase faster than the tank surface which soon becomes inadequate Various methods have been developed to get the heat out of the tank more effectively Large power transformer being built today are commonly of the forced-oil-cooled type In this design the oil is pumped both through the external cooling devices(air or water heat-exchangers)and through internal channels that are located nearest the points where the heat is generated Thus the transfer of heat to and from the oil is far more effective than in the plain self-cooled or fan-cooled unit where the oil is allowed to circulate by convection. When oil-to-air heat exchanger(a group fans on each radiator)is used, this cooling type is designated as type of FOA While oil-to-water heat exchanger is used, it is called FOW 許多變壓器 ,包括所有的大的和所有高電壓的沉浸在礦物油 的雙重目的服務(wù)的冷卻和絕緣繞。小型變壓器有足夠的容器表面輻射熱量減去所引起的損失而不超過允許的溫度 rise.As 尺寸增加 ,損失增加的速度比坦克表面 ,很快就變成inadequate.Various 方法已經(jīng)發(fā)展到過熱的坦克正在建造更 effectively.Large 電力變壓器今天的 type.In一般 forced-oil-cooled這個設(shè)計中被抽同時通過外部冷卻設(shè)備 (空氣或水密閉式畜禽 )和通過內(nèi)部通道 ,通道位于在最近的點 generated.Thus 熱量轉(zhuǎn)移的熱量和從石油遠比在平原更有效 self-cooled或 fan-cooled單元中時 ,其石油是允許流通的對流。當 oil-to-air換熱器 (一群球迷在每個散熱器 )使用 ,這種冷卻式被指定為類型的 FOA.While oil-to-water換熱器使用 ,它被稱為 FOW。 偉大多臺變壓器,包括所有大型的和所有高電壓的沉浸在礦物油的冷卻和絕緣繞組的雙重目的。小變壓器有足夠罐表面輻射的 a11 引起他們的損失不超過允許的溫度 rise As 大小 increases, the 損失增加得更快,很快就將成為 inadequate Various 方法的油箱表面的熱已開發(fā)可以得 到的罐內(nèi)熱今天正在興建更多 effectively Large 電力變壓器是常用的強迫油冷 type In 這油抽水都通過外部冷卻設(shè)備 (空氣或水熱交換器) 的設(shè)計和通過內(nèi)部渠道位于最近的熱量在哪里 generated Thus 的點的傳熱和油是比在油流通獲對流的普通自冷或風扇冷卻的裝置有效得多。當油 -空氣換熱器 (每個散熱器組風扇) 是 used, this 冷卻類型被指定為 FOA While 油 -水換熱器的類型是 used, it 被稱為 FOW For applications where any liquid, even a nonflammable one, is objectionable,the dry-type transformer is used The ventilated dry-type unit is cooled by a continuous natural draft of air and consequently is not suitable for locations where the air is wet or dirty. For these locations a completely enclosed unit, the sealed dry-type,is available, having a core-and-coil in a tank that is sealed and filled with an insulating gas. Dry-type transformers are completely nonflammable, using organic material such as epoxy resin. 為應(yīng)用程序的任何 liquid, even 不可燃 one, is objectionable,the 型干式變壓器在哪里 used The 通風的干式單位由連續(xù)的自然通風的空氣冷卻和因此不適合那里的空氣是濕或骯臟的位置。為這些位置完全封閉的 unit, the 密封干 type, is available,having 核心 -和線圈被密封和裝滿絕緣氣體的容器。干式變壓器完全是 nonflammable, using 有機材料如環(huán)氧樹脂。 可應(yīng)用在任何液體 ,甚至是一種難燃的人 ,是令人討厭的 ,變壓器通風產(chǎn)品結(jié)構(gòu)設(shè)計和冷卻市區(qū)單位由連續(xù)的自然通風的空氣 ,因此 不適合場所空氣潮濕或臟。為這些位置完全封閉的單位、密封結(jié)構(gòu) ,是可行的 ,有一個 core-and-coil密封在一個魚缸 ,并充滿了一種絕緣氣體。變壓器結(jié)構(gòu)設(shè)計是完全不可燃 ,使用環(huán)氧樹脂有機物質(zhì)。 Circuit Breaks 電路符 電路打破 Within a few years of the introduction of the fuse, the growing electrical industry started looking for an alternative method of providing protection for electric circuits They wanted a device that would not be destroyed by its operation, that could simply be reset to restore power, and that could also be used as a means of switching for the circuit Out of this development work came the circuit breaker which is an electromechanical device The circuit breaker is defined as a device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined over-current without injure to itself when properly applied within its rating. As with other equipment, circuit breakers are divided into those rated for 1 000 volts and less and those rated for more than 1000 volts Low-voltage circuit breakers were also divided into two distinct categories , molded-case and power types However, in the past few years the distinction between these two types has become less clea-cut as a new type of encased breaker are universally operated in air, so it is not necessary to designate them as air circuit breakers as this understood Medium and highvoltage breakers, on the other hand, use mediums other than air in which to open the circuit and therefore must be designated as being air, gas, and so on 在短短幾年內(nèi)引進的保險絲 ,日益擴大的電氣工業(yè)開始 尋找一個替代方法的電力 circuits.They 想要提供保護裝置 ,不會破壞其運行 ,那可能只是被重置為恢復供電 ,也可以使用的一種手段 circuit.Out 切換的開發(fā)工作的電路 breaker.which 來為機電一體化裝置 ,斷路器被定義為一種裝置 ,用來實現(xiàn)一個電路開啟和關(guān)閉非自動化手段和打開電路自動上預(yù)定過流沒有傷害到其自身在適當?shù)膽?yīng)用其信用評級。 與其他設(shè)備、斷路器分為 1 000 伏被評為越來越被評為超過 1000 volts.Low-voltage 斷路器也被分為兩大類 ,types.However molded-case 和力量 ,在過去幾年中區(qū)別這兩種類型已變得更有 clea-cut 作為一種新型被普遍地在空氣斷路器操作 ,所以 沒有必要指定它們 ,因為這 understood.Medium 空氣斷路器和高壓斷路器 ,另一方面 ,使用介質(zhì)的空氣中 ,除了開電路 ,因此必須被指定為被空氣、煤氣、等等
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