電氣專業(yè)畢業(yè)設(shè)計外文翻譯----電力變壓器工作原理-電氣類-wenkub
2023-05-18 20:27:45 本頁面
【正文】 y 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, where φm is the maximum value of the core flux。 and (2) it provides a ponent to account for the hysteresis and eddy current losses in the core. There bined losses are normally referred to as the core losses. The noload current Iθ is usually few percent of the rated fullload current of the transformer (about 2 to 5%). Since at noload the primary winding acts as a large reactance due to the iron core, the noload current will lag the primary voltage by nearly 90186。, therefore, they are 180186。 that is, it has no losses. Thus Pm = Pout or VpIp primary PF = VsIs secondary PF where PF is the power factor. For the abovestated assumption it means that the power factor on primary and secondary sides are equal。本文我們討論的原則和電力變壓器的應用。 變壓器是高效率的，因為它沒有旋轉(zhuǎn)損失，因此在電壓等級轉(zhuǎn)換的過程中，能量損失比較少。磁通連接的第二個繞組被稱為變壓器的二次側(cè)繞組或者是副邊。 3. 變壓器的工作原理 當二次側(cè)電路開路是，即使原邊被施以正弦電壓 oV ，也是沒有能量轉(zhuǎn)移的。 變壓器空載電流 sI 一般大約只有滿載電流的 2%— 5%。 第二個分量 Ie=I0sinθ0，與原邊電壓同相。 如果假定變壓器中沒有其他的電能損耗一次側(cè)的感應電動勢 Ep 和二次側(cè)的感應電壓 Es 可以表示出來。因此，它于施加的電壓有180186。因此原邊電壓很小，并且 Vp 的值近乎等于Ep。從交流 電原理可知，有效值是一個正弦波，其值為平均電壓的 倍；因此 E = m? 因為一次側(cè)繞組和二次側(cè)繞組的磁通相等，所以繞組中每匝的電壓也相同。實際上我們是考慮一臺理想 狀態(tài)下的變壓器；這意味著它沒有任何損耗。為了計算電壓，我們需要更多數(shù)據(jù)。如果這個電壓是升高的，它就是一個升壓變壓器。因此，我們把這種類型的變壓器稱為絕緣型變壓器。從等式 psVV = psII ≌ psEE ≌ a 中我們可知 Vp = aVs 并且 Ip = Is/a。 。我們把這種折算方式稱為負載阻抗向一次側(cè)的折算。在第四部分我們會了解到當變壓器帶負荷運行時一次側(cè)繞組電流是如何隨著二次側(cè)負荷電流變化而變化的。當 a=1 時，變壓器的二次側(cè)電壓就等于起一次側(cè)電壓。實際上 , 變比從標識牌數(shù)據(jù)獲得 , 列出在滿載情況下原邊和副邊電壓。在上面公式中一次
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