變壓器畢業(yè)設(shè)計(jì)外文翻譯-其他專業(yè)-文庫(kù)吧
2024-12-30 08:12 本頁(yè)面
【正文】 次側(cè)中的磁動(dòng)勢(shì)減小磁通的趨勢(shì)。 總的來(lái)說(shuō)，變壓器為了保持磁通是常數(shù)，對(duì)磁通變化的響應(yīng)是瞬時(shí)的。更重要的是，在空載和滿載時(shí)，主磁通 φ0的降落是很少的（一般在） 1 至 3%。其需要的條件是 E 降落很多來(lái)使電流 Ip 增加。 在一次側(cè)，電流 Ip’在 一次側(cè)流過(guò)以平衡 Is 產(chǎn)生的影響。它的磁動(dòng)勢(shì) NpIp’只停留在一次側(cè)。因?yàn)殍F芯的磁通 φ0保持不變，變壓器空載時(shí)空載電流 I0必定會(huì)為其提供能量。故一次側(cè)電流 Ip 是電流 Ip’與 I0’的和。 因?yàn)榭蛰d電流相對(duì)較小，那么一次側(cè)的安匝數(shù)與二次側(cè)的安匝數(shù)相等的假設(shè)是成立的。因?yàn)樵谶@種狀況下鐵芯的磁通是恒定的。因此我們?nèi)耘f可以認(rèn)定空載電流 I0相對(duì)于滿載電流是極其小的。 當(dāng)一個(gè)電流流過(guò)二次側(cè)繞組，它的磁動(dòng)勢(shì)（ NsIs）將產(chǎn)生一個(gè)磁通，于空載電流 I0產(chǎn)生的磁通 φ0不同，它只停留在二次側(cè)繞組中。因?yàn)檫@個(gè)磁通不流過(guò)一次側(cè)繞組，所以 它不是一個(gè)公共磁通。 另外，流過(guò)一次側(cè)繞組的負(fù)載電流只在一次側(cè)繞組中產(chǎn)生磁通，這個(gè)磁通被稱為一次側(cè)的漏磁。二次側(cè)漏磁將使電壓增大以保持兩側(cè)電壓的平衡。一次側(cè)漏磁也一樣。因此，這兩個(gè)增大的電壓具有電壓降的性質(zhì)，總稱為漏電抗電壓降。另外，兩側(cè)繞組同樣具有阻抗，這也將產(chǎn)生一個(gè)電阻壓降。把這些附加的電壓降也考慮在內(nèi)，這樣一個(gè)實(shí)際的變壓器的等值電路圖就完成了。由于分支勵(lì)磁體現(xiàn)在電流里，為了分析我們可以將它忽略。這就符我們前面計(jì)算中可以忽略空載電流的假設(shè)。這證明了它對(duì)我們分析變壓器時(shí)所產(chǎn)生的影響微乎其微。因?yàn)殡妷航蹬c負(fù) 載電流成比例關(guān)系，這就意味著空載情況下一次側(cè)和二次側(cè)繞組的電壓降都為零。 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。 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 6 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. Th
環(huán)評(píng)公示相關(guān)推薦
鄂ICP備17016276號(hào)-1