《变压器-毕业论文外文翻译.pdf》由会员分享，可在线阅读，更多相关《变压器-毕业论文外文翻译.pdf（5页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、 英文资料及其翻译 Transformer Types and Construction of Transformer A transformer is a device that alternating current electric energy at one voltage level into alternating current electric energy at another voltage level through the action of a magnetic field.It consists of two or more coils wire wrapped a
2、round a common ferromagnetic core.These coils are(usually)not directly connected.The only connection between the coils is the common magnectic flux presen within the core.One of the transformer windings is connected to a source of ac electric power,and the second(and perhaps third)transformer windin
3、g supplies electric power to loads.the transformer winding connected to the power souce is called the primary winding or input winding.and the winding connected to the loads is called the secondary winding or input winding.If there is a third winding on the transformer,it is called the tertiary wind
4、ing.Power transformer are constructed on one of two types of cores.one type of construction consists of a simple rectangular laminated piece of steel with the transformer windings wrapped around two sides of the rectangle.This type of construction is know as coreform.The other type consists of three
5、-legged laminated core with the windings wrapped around the center leg.This type of construction is know as shell form.In either case,the core is constructed of thin laminations electrically isolated form each other in order in order to reduce eddy currents to a minimum.The primary and secondary win
6、dings in a physical transformer are wrapped one on top of the other with the low-voltage winding innermost.Such an arrangement severs two purposes:1.It simplifies the problem of insulating the high-voltage winding from the core.2.It results in much less leakage flux than would be the two windings we
7、re separated by a distance on the core.Power transformer are given a variety of different names,depending on their use in power systems.A transformer connected to the output of a generator and used to step its voltage up to transformer levels is sometimes called unit transformer.The transformer ai t
8、he other end of the transformer line,which steps the voltage down from transmission levels to distribution levels,is called a substation transformer.Finally,the transformer that takes the distribution voltage and steps is down to the final voltage ai which the power is actually used is called a dist
9、ribution transformer.All these devices are essentially the same-the only difference among them is their intended use.In addition to the various power transformer,two special-purpose transformers are used with electric machinery and power systems.The first of these special transformers is a device sp
10、ecially designed to sample a high voltage and produce a low secondary voltage directly proportional to it.Such a transformer is called a potential transformer.A power transformer also produces a secondary voltage directly proportional to its primary voltage;the difference between a potential transfo
11、rmer and a power transformer is that the potential transformer is designed to handle only a very small current.The second type of special transformer is a device designed to provide a secondary current.much smaller than but directly proportional to its primary current.This device is called a current
12、 transformer.Cirtcuit Breakers A circuit breaker is mechanical switching device capable of making,and breaking currents under normal circuit conditions and also making.carring for a specified time,and mediujm in which circuit interruption is performed may be designated by a suitable prefix,for examp
13、le,air-blastcircuit breaker,oil circuit breaker.The circuit breakers currently in use can be dlassified into the following categories according to the arc-quenching principles:air swetches oel ciryit breakers,minmum-oil circuit breakers,air-blast circuit breakers,the magenetic air circuit breakers,m
14、inimum-oilcircuit breakers,aer-blast circuit breakers,the by voltage,insulation levelcurrent,interrupting capabilities,transient recovery coltage,interrupting tiome,and trip delay.The nameplate on a circuit breaker usually indicates:.The maximum steady-state current it can carry,2.The maximum interr
15、upting current,3.The maximum line voltage,4.The interrupting time in cycles,The interrupting time in may last form 3 to 8 cycles on a 60 Hz system.To interrubt large currents quickly,we have to ensure rapid cooling.High-speed interruption lunits the damage transmission lines and equipment and,equall
16、y important,it helps to mainmain the stability of the system whenever a contingency occurs.The main parts of a circuit breaker are usually:arc-quenching chamber(or interrupter with moving and fixed contacts)operating mechanism and supporting structures.Air Switches-With increasing currents and volta
17、ges,spring-action driving mechanisms were developed to reduce contact buring by faster-opening operation.Later,main contacts were fitted with arcing contacts of special material and shape,which opend after and closed before the main contacts.Further improvements of the air switch were the bursh-type
18、 contact with a wiping and cleaning function,the insulating barrier leading to arc chutes,and blowout coils with excellent arc-extinguishing properties.These features,as well as the horn gap contact,are still in use in low voltage as and de breakers.Oil Circuit Breaker Around 1900,in order to cope w
19、ith the new requirement for“interrupting capacity”,AC switches were immersed in a tank of oil.Is very effective in quenching the arc and establishing the open break after current zero.Deion grids,oil-blast features,pressure-tight joints and vents,new operating mechanisims,and multiple interrupter we
20、re introucedover several decades to make the oil circuit breaker a reliable apparatus for system voltage up to 362kV 变压器 变压器的类型和结构 变压器是一个通过磁场作用将一个交流电压值变成另一个电压值的设备。它由两条或更多的金属丝缠绕在一个核心磁铁上组成的。这些绕线（一般）不直接接触。绕线之间唯一的联系是它们共有的存在于磁芯的磁通量。一组变压器绕组连接到一个交流电源上，同时第二组（或许第三组）变压器绕组作为电源提供给负载。连接到电源上的变压器绕组叫做一次绕组，或者输入绕组。连接
21、负载的绕组叫做二次绕组或者输出绕组。如果变压器上有第三绕组，它叫做三次绕组。电力变压器由一两种磁芯中的一种构成。一种构造是由一种简单的变压器绕组缠绕在矩形两边的矩形薄钢片组成。这种构造类型被认为是核心形式。另一种类型是由绕组缠绕在中心引脚的叠片铁心构成。这种构造类型贝壳形式。其中任意一种类型，磁心都是由排列整齐的彼此之间电气隔离的薄铁片构成，以便将涡流减小到最小值。一个物理变压器的一次绕组和二次绕组被缠绕成一个在内部的另一个低压绕组的上面。这样安排达到了两个目的：1.它简化了从磁芯到高压绕组的绝缘问题。2.与过去将两个绕组在磁心上隔离一定距离比起来，它导致更少的漏通量。电力变压器被赋予了很多不
22、同的名字，取决于它们在当前系统中的作用。一变压器连接到一个发电机的输出端，并且用于步调它的电压达到变压器值有时被叫做单位变压器。变压器一个排在另一个后面将电压从传送值步降到分布值，被叫做变电站。最后，变压器将分布电压和步幅降到最后的实际使用的电能被叫做发送变压器。所有这些设备本质上都是相同的它们之间唯一不同的是它们的特定用途。断路器 空气压缩断路器是一种机械开关设备，能够在正常和特殊情况下开断电流（比如说短路电流）。例如空气断路器、油断路器，干扰电路的导体因该安全可靠的应用于其中，电流断路器按灭弧远离通常被分为如下等级：空气开关断路器、油断路器、少油断路器、压缩空气断路器、具有消磁性质的隔离开
23、关、六氟化硫断路器和真空断路器。他们的参数有电压等级、绝缘等级、电流开断容量、开断时间的瞬时电压恢复和条炸事件。断路器的铭牌通常包括：1.最大可承受电流；2.最大中断电流；3.最大线路电压；4.中断周期数量。在 60HZ的系统中，中断可能持续 3 至 8 个周期，为了快速中断达负荷电流，我们不得不确保它的持续冷却，、高速开断能限制对传输线路的损害，这一点是同等重要的它帮助系统在任何事故发生时维持稳定运行，断路器主要由操作机构、执行机构和灭弧室组成。当有触发电流或者电压时，空气隔离开关的弹簧操作机构迅速动作以用来减少触点的烧损，主触点的特殊形状和使用材料完全适合电弧的接触，空气隔离开关更进一步的改进是由于灭弧的性能、绝缘隔板组成的灭弧罩、带灭弧功能的触头等这些特殊性质，所以仍被应用于低电压等级和直流断路器中。多油断路器出现于 1900前后，主要用来满足新的开断容量的要求，交流开关被浸入一个油缸之中，油在熄灭电弧和在电流过零时建立开断功能是十分有效，灭弧栅、喷油嘴、新的操作机构和多种新的断路功能在近几十年引进使用多油断路器能够适应 362kV。