變壓器畢業(yè)設計外文翻譯-其他專業(yè)-文庫吧資料
2025-01-27 08:12本頁面
【正文】 te 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。, therefore, they are 180186。 in phase behind the primary voltage VP. It is this ponent that sets up the flux in the core。 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。 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。這證明了它對我們分析變壓器時所產(chǎn)生的影響微乎其微。由于分支勵磁體現(xiàn)在電流里，為了分析我們可以將它忽略。另外，兩側繞組同樣具有阻抗，這也將產(chǎn)生一個電阻壓降。一次側漏磁也一樣。 另外，流過一次側繞組的負載電流只在一次側繞組中產(chǎn)生磁通，這個磁通被稱為一次側的漏磁。 當一個電流流過二次側繞組，它的磁動勢（ NsIs）將產(chǎn)生一個磁通，于空載電流 I0產(chǎn)生的磁通 φ0不同，它只停留在二次側繞組中。因為在這種狀況下鐵芯的磁通是恒定的。故一次側電流 Ip 是電流 Ip’與 I0’的和。它的磁動勢 NpIp’只停留在一次側。其需要的條件是 E 降落很多來使電流 Ip 增加。 總的來說，變壓器為了保持磁通是常數(shù)，對磁通變化的響應是瞬時的。感應電壓的減小將使外施電壓和感應電動勢之間的差值更大，它將使初級線圈
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