電氣專(zhuān)業(yè)畢業(yè)設(shè)計(jì)外文翻譯----電力變壓器工作原理-電氣類(lèi)(存儲(chǔ)版)
【正文】 ly 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。 thus the induced quantities Ep and Es vary as a sine function. The average value of the induced voltage given by 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。兩個(gè)線(xiàn)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(jiàn)電流分量 mI = I0sinθ0，被稱(chēng)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(guò)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 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(huà)說(shuō)，一次側(cè)和二次側(cè)電流比與匝數(shù)比成反比。當(dāng) a=1 時(shí)，變壓器的二次側(cè)電壓就等于起一次側(cè)電壓。我們把這種折算方式稱(chēng)為負(fù)載阻抗向一次側(cè)的折算。從等式 psVV = psII ≌ psEE ≌ a 中我們可知 Vp = aVs 并且 Ip = Is/a。如果這個(gè)電壓是升高的，它就是一個(gè)升壓變壓器。實(shí)際上我們是考慮一臺(tái)理想 狀態(tài)下的變壓器；這意味著它沒(méi)有任何損耗。因此原邊電壓很小，并且 Vp 的值近乎等于Ep。 如果假定變壓器中沒(méi)有其他的電能損耗一次側(cè)的感應(yīng)電動(dòng)勢(shì) Ep 和二次側(cè)的感應(yīng)電壓 Es 可以表示出來(lái)。 變壓器空載電流 sI 一般大約只有滿(mǎn)載電流的 2%— 5%。磁通連接的第二個(gè)繞組被稱(chēng)為變壓器的二次側(cè)繞組或者是副邊。本文我們討論的原則和電力變壓器的應(yīng)用。, therefore, they are 180186。 therefore, it induces a voltage in the secondary by electromagic induction in accordance with Lenz’s law. Thus the primary receives its power from the source while the secondary supplies this power to the load. This action is known as transformer action. 3. TRANSFORMER PRINCIPLES When a sinusoidal voltage Vp is applied to the primary with the secondary opencircuited, there will be no energy transfer. The impressed voltage causes a small current Iθ to flow in the primary winding. This noload current has two functions: (1) it produces the magic flux in the core, which varies sinusoidally between zero and ? φm,
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