變壓器畢業(yè)設(shè)計(jì)外文翻譯-其他專業(yè)(存儲(chǔ)版)
【正文】 rage value of the induced voltage given by 7 Eavg = turns c h a n g e in flu x in a g iv e n tim eg iv e n tim e which is Faraday’s law applied to a finite time interval. It follows that Eavg = N 21/(2 )mf? = 4fNφm which N is the number of turns on the winding. Form ac circuit theory, the effective or rootmeansquare (rms) voltage for a sine wave is times the average voltage。 5 TRANSFORMER Abstract: The transformer is the transformer substation majpor installation,the function realizes the work voltage rank transformation ,the key job principle is the electromagic the substation is realizes the voltage class transformation and the electrical energy assignment place .Carries on the voltage class transformation to the electric power supply,deals with the place which the electrical enrtgy carries on redistributes to be called the transformer the transformer substation is for electrical power distribution system’s key position,the electric power supply directs the transformer substation form the electrical work,pletes the voltage dropping in the transformer substation, functions and so on electrical energy assignment 1. INTRODUCTION The highvoltage transmission was need for the case electrical power is to be provided at considerable distance from a generating station. At some point this high voltage must be reduced, because ultimately is must supply a load. The transformer makes it possible for various parts of a power system to operate at different voltage levels. In this paper we discuss power transformer principles and applications. 2. TOWWINDING TRANSFORMERS A transformer in its simplest form consists of two stationary coils coupled by a mutual magic flux. The coils are said to be mutually coupled because they link a mon flux. In power applications, laminated steel core transformers (to which this paper is restricted) are used. Transformers are efficient because the rotational losses normally associated with rotating machine are absent, so relatively little power is lost when transforming power from one voltage level to another. Typical efficiencies are in the range 92 to 99%, the higher values applying to the larger power transformers. The current flowing in the coil connected to the ac source is called the primary winding or simply the primary. It sets up the flux φ in the core, which varies periodically both in magnitude and direction. The flux links the second coil, called the secondary winding or simply secondary. The flux is changing。一次側(cè)漏磁也一樣。故一次側(cè)電流 Ip 是電流 Ip’與 I0’的和。感應(yīng)電壓的減小將使外施電壓和感應(yīng)電動(dòng)勢(shì)之間的差值更大，它將使初級(jí)線圈中流過更大的電流。換句話說，極性的標(biāo)注可以表明當(dāng)電流流過兩側(cè)的線圈時(shí)，線圈中的磁動(dòng)勢(shì)會(huì)增加。 從電源側(cè)來看變壓器，其阻抗可認(rèn)為等于 Vp / Ip。 當(dāng)副邊電壓 Vs 相對(duì)于原邊電壓減小時(shí)，這個(gè)變壓器就叫做降壓變壓器。用字母 a 來表示這個(gè)比率，如下式 a = psEE = psNN 假設(shè)變壓器輸出電能等于其輸入電能 —— 這個(gè)假設(shè)適用于高效率的變壓器。一次側(cè)空載電流很小，僅為滿載電流的百分之幾。這種情況是非線性鐵芯材料 造成的。這兩種相關(guān)的損耗被稱為鐵芯損 耗。它在鐵圈中建立了磁通 φ，它的幅值和方向都會(huì)發(fā)生周期性的變化。變壓器能使電力系統(tǒng)各個(gè)部分運(yùn)行在電壓不同的等級(jí)。變配電所是實(shí)現(xiàn)電壓等級(jí)變換和電能分配的場(chǎng)所。兩個(gè)線圈之所以相互耦合，是因?yàn)樗鼈冞B接著共同的磁通。變壓器在原邊接收電能的同時(shí)也在向副邊所帶的負(fù)荷輸送電能。顯然可見電流分量 Im= I0sinθ0，被稱做勵(lì)磁電流，它在相位上滯后于原邊電壓 VP 90186。相同的磁通會(huì)通過原邊自身，產(chǎn)生一個(gè)電動(dòng)勢(shì) Ep。產(chǎn)生電壓的平均值如下 Eavg = turns給 定 時(shí) 間 內(nèi) 磁 通 變 化 量給 定 時(shí) 間 即是法拉第定律在瞬時(shí)時(shí)間里的應(yīng)用。在上面公式中一次側(cè)和二次側(cè)的功率因素是相等的；因此 3 VpIp = VsIs 從上式我們可以得知 psVV = psII ≌ psEE ≌ a 它表明端電壓比等于匝數(shù)比，換句話說，一次側(cè)和二次側(cè)電流
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