電氣專(zhuān)業(yè)畢業(yè)設(shè)計(jì)外文翻譯-在線(xiàn)瀏覽
2024-08-01 05:41本頁(yè)面
【正文】 rating of the fuse is such as to product conductor temperatures far below this maximum limit. Nevertheless, the I rating of the conductor is an important element in the choice of the fuse. Electrical installation in buildings The electrical distribution system in a building is the final link between the consumer and the original source of electrical energy. All such inhouse distribution systems, be they large or small, must meet certain basic requirements:1. Safety a. Protection against electric shock b. Protection of conductors against physical damage c. Protection against overloads d. Protection against hostile environments 2. Conductor voltage drop It should not exceed 1 or 2 percent 3. Life expectancy The distribution system should last a minimum of 50 years 4. Economy The cost of the installation should be minimized while observing the pertinent standards. Standards are set by the National Electrical Code and every electrical installation must be approved by an inspector before it can be put into service. Principal ponents of an electrical installation Many ponents are used in the markup of an electrical installation. The block diagrams of and , together with the following definitions, will help the reader understand the purpose of some of the more important items.1. Service Conductors. These are the conductors that extend form the street main or form a transformer to the service equipment on the consumer premises.2. Service Equipment. The necessary equipment, usually consisting of a circuit breaker or switch and fuses, and their accessories, located near the point of entrance of service conductors to a building or other structure, or an otherwise defined area, and intended to constitute the main control and means of cutoff of the supply.3. Meeting Equipment. Various meters and recorders to indicate the electrical energy consumed on the premises.4. Panel Board. A single panel or group of panel units designed for assembly in the form of a single panel。從核安全的角度考慮，操作反饋的主要目標(biāo)如下：1 確認(rèn)可導(dǎo)致更為嚴(yán)重事故的預(yù)兆事故，以明確和貫徹在這類(lèi)事故發(fā)生前所需采取的改正措施；2 利用標(biāo)準(zhǔn)的機(jī)組（事故的一般方面，從修改研究等方面獲取最大的效益）3 如有必須修改之處，那么在將原理推廣到整個(gè)電廠(chǎng)序列之前，要保證不會(huì)產(chǎn)生相反的副作用；4 要利用在機(jī)組實(shí)際運(yùn)行中所獲得的數(shù)據(jù)，以統(tǒng)一安全標(biāo)準(zhǔn)，特別是對(duì)新廠(chǎng)更需要如此。提高安全水平，操作經(jīng)驗(yàn)反饋由EDF采用的標(biāo)準(zhǔn)政策（EDF是一種主要PWR系統(tǒng)類(lèi)型和有限的單個(gè)電廠(chǎng)序列數(shù)量）可保證通過(guò)特別重視預(yù)兆的分析極大的提高操作經(jīng)驗(yàn)的價(jià)值。按照安全重要系統(tǒng)（IPS）進(jìn)行一項(xiàng)詳盡無(wú)疑的分析，同樣也是為了確定哪一種設(shè)備需要進(jìn)行定期的檢測(cè)，哪一項(xiàng)無(wú)需檢測(cè)（正常運(yùn)行就是運(yùn)行狀況良好的充分證明）。保持安全水平為了保持安全水平，首先必須遵守設(shè)計(jì)所規(guī)定的運(yùn)行限制。4 鑲板 一個(gè)盤(pán)區(qū)或小組盤(pán)區(qū)單位為匯編設(shè)計(jì)了以一個(gè)唯一盤(pán)區(qū)的形式。 2. 服務(wù)設(shè)備 這些是必要的設(shè)備，通常包括開(kāi)關(guān)或開(kāi)關(guān)和保險(xiǎn)絲以及他們的輔助部件，位于大廈或者其它結(jié)構(gòu)服務(wù)導(dǎo)體的入口處，或是一個(gè)其他方面被定義的區(qū)域和意欲構(gòu)成主控制和切斷供應(yīng)的方法。 ，與以下定義一起，將幫助讀者了解某些更加重要的項(xiàng)目的意義。 標(biāo)準(zhǔn)由全國(guó)電子代碼規(guī)定，并且電子設(shè)施在它可以被放入服務(wù)之前必須由審查員批準(zhǔn)。 在建筑內(nèi)的電子設(shè)備安裝 電子分布式系統(tǒng)在建筑內(nèi)是消費(fèi)者和電能初始源之間最后的鏈接。 實(shí)踐上，保險(xiǎn)絲的規(guī)定值遠(yuǎn)在產(chǎn)生導(dǎo)體溫度的最大限度之下。 保險(xiǎn)絲是經(jīng)過(guò)選擇的，目的是它的規(guī)定值比將保護(hù)導(dǎo)體上升的過(guò)熱溫度要少。 如果它最初的溫度是50，計(jì)算以下： (銅熔化在1083) ，需要熔化導(dǎo)線(xiàn)的時(shí)間 解答 =197 A
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