《输电线路专业英语》Unit Two

Generators and Motors 电机的分类

按在应用中的职能来分： 发电机 (generator) ；电动机 (motor) ；变压器 (transformer) ；

变流器 (convertor) ；变频器 (transducer)

按电流种类分： 直流 (direct current) 电机 交流 (alternating current) 电机

按速度分： 直流电机；变压器；异步 (asynchronous) 电机；同步 (synchr

onous) 电机

电机的两个基本原理： 1. A moving charge in a magnetic field exper

iences a force.A charge q moving with a speed v relative to a

magnetic field B experiences a force F equal to F=qvBsinθ, where θ is the angle between the direction of the field and the direction of the charge’s velocity.

The force is in a direction that is perpendicular to both the velocity and the field as given by the ‘right-hand rule’.

For a positive charged particle moving (velocity v) in a magnetic field (field B) the direction of the resultant force (force F) can be found by: 1) Thumb of right hand in direction of Velocity, v (first vector); 2) Index Finger of r.h. in direction of field, B (second vector); 3) Your Palm (or middle finger if you like) now points in the direction of the Force, F (final vector)

2. A moving charge generates its own magnetic field. （右手螺旋定理） In particular for our purposes here, an electric current pr

oduces a magnetic field. The field encircles the current, as given by another ‘right-hand rule’.

If the right thumb points in the direction of conventional current (moving positive charges), the fingers of the right hand curl around the wire in the direction of the magnetic field.

拇指 thumb 食指 forefinger; index finger; first finger 中指 middle finger 无名指 ring finger; third finger 小指 little finger

New words1. induce

引诱；诱导 Nothing shall induce me to join their club. 我怎么都不会去加入他们的俱乐部。

招致；引起 Too much food induces sleepiness. 吃得过饱会产生睡意。

感应：通过感应而产生（电流或电磁） To produce (an electric current or a magnetic charge) by induction.

induced circuit 感应电路 induced current 诱导 [ 感生 ] 电流 induced electromotive force 感应电动势

induction n.① 就任；征召；介绍 ②诱导；引诱 ③加入工作；加入组织④ 〈电〉感应 ⑤归纳；归纳法；归纳所得之结论

2. fluxn. 涨潮 , 变迁 , [ 物 ] 流量 , 通量

be in flux 不断变动 magnetic flux 磁通量 flux and reflux 潮涨潮落 ; [ 喻 ] 不断消长 , 不断变化 These graduates haven't found jobs yet; to them ever

ything is in a state of flux. 这些毕业生尚未找到工作 , 所以对他们来说 , 一切都变

化莫测。vi. 熔化 , 流出vt. 使熔融 , 用焊剂处理

3. motionn. 运动

chaos motion 不规则运动 motion and rest 运动和静止 You must not get out of the car when it is in motion. 汽车行驶的时候千万不能下车。

vt. （常与 to 连用）用动作打信号；打手势 She motioned to the waiter. 她向侍者打了个手势。

4. stator n. 定子：发动机、发电机、涡轮或其它机器中的不动部分，转子绕

其旋转 rotor

（电机的）转子 （直升机的）水平旋翼

bearing 轴承：在机器两个固定运动部分之间起支撑、引导或减少运动摩擦

的装置 关系，关联：相关的关系或内部联系：

Those issues have no bearing on our situation. 那些问题与我们的情况无关

举止，风度：一个人的行为方式 “That is Claudio. I know him by his bearing” (Shakespeare). “ 那是克劳迪欧，一看他的样子就能认出来”（莎士比亚）。

shaft 轴 , 杆状物

5. stationary adj. 静止的 Not moving. 不能被移动的；固定的 Not capable of being moved; fix

ed. 不变的 Unchanging:

a stationary sound. 稳定的声音

6. rotor 7. bearing 8. shaft 9. housing

房屋﹑ 住宅 机器等的防护外壳或外罩

10. alternate adj. 交替的 , 轮流的 , 预备的

an alternate plan. 供替换的计划

v. 交替 , 轮流 , 改变 The weather alternates between sunshine and rain. 时而天晴 , 时而下雨。

11. alternator 交流发电机

three-phase alternator三相交流发电机 AC = alternating current DC = direct current director

n.主任 , 主管 , 导演 , ( 机关 )首长 , (团体 ) 理事 , (公司 )董事 , 指挥仪 , 控制器

12. windmill n. 风车 , 风车房 , 旋转玩具 vt. 使旋转 vi. 作风车般旋转

tilt at windmills 与假想的对手作战：面对假想的敌人或威胁；同假想的敌人或威胁作战

13. hydro-turbine n. 水轮机

14. diesel n.柴油（发动）机

15. crank adj.脾气暴燥的 , 易怒的 n.[ 机 ]曲柄 , 奇想 vt.[ 机 ] 装曲柄

16. torque n. 转矩；扭矩

17. tighten vt. 使变紧，使绷紧

tighten one's belt 束紧腰带 , 节约度日

tight adj. 紧的 , 绷紧的 , 紧密的 , 不漏水 ( 不透气 ) 的 , 由压迫产生的 , 困难的 , 吝啬的 , 严厉的

adv. 紧紧地 loose 18. wrench

n.伤别；别离的痛苦 ,扳钳 , 扳手 the wrench of leaving home 离家的悲痛

vt.扭伤 to wrench one's ankle 扭伤某人的脚脖子

19. proportional 比例上的 成比例的；相称的

Punishment ought to be proportional to the crime. 惩罚应该与所犯的罪相应

20. equation n. 【数学】等式 , 方程式【化学】化学方程式 equations set 方程组

21. conventional adj. 因袭的；传统的，习惯的

conventional accounting 传统会计（不使用计算机，依靠人工记帐的会计）

常规的；普通平凡的 conventional weapon 常规武器

22. abbreviation 缩写，缩写式

23. requirement 需要，要求

Phrases and Expressions 1. generator action 发电机作用 2. motor action 电动机作用 3. be coupled to 与…联结 4. steam and hydro-turbine 汽（水）轮机 5. prime mover 原动机 6. DC generator 直流发电机 7. alternating current 交流；交流发电机 8. diesel and jet engine 柴油机和喷气发动机 9. hand crank 手摇曲柄 10. be proportional to 与…成比例 11. tend to 走向；趋向；倾向 12. torque requirement 转矩要求

补充生词 high-voltage:高压 high-tension line :高压线路 distributing substation:配电变电站 in parallel: 并联 damaged section: 故障段 power-factor-correcting : 功率因数补偿 step up: 升高电压 step down :降低电压 frequency changer : 变频器 phase converter : 换相器

Generators and Motors

Generators change mechanical energy into electrical energy. Motors change electrical energy into mechanical energy.

Generators and motors are a lot alike. They are made in the same general way. Further, they both depend on the same electromagnetic principle for their operation.

The first principle is called GENERATOR ACTION. It is also called INDUCTION. Voltage can be induced into a wire that is in a magnetic field. This happens when the magnetic flux is cut by the wire. In some cases, the wire moves. In other cases, the field moves. In still others, both are moving, but at different speeds. It takes mechanical energy to cause the motion. This motion causes electricity to be generated.

The second principle is called MOTOR ACTION. This is simply the mechanical forces between magnets. When two magnets (or electromagnets) approach each other, one will be either pulled toward or pushed away from the other.

Some motors use one permanent magnet and one electromagnet. Others use two electromagnets. Either way, electrical energy creates at least one of the magnetic fields. Then, the forces between the two magnetic fields cause the motion.

CONSTRUCTION Each type of motor and generator is build to

do its own special job. All of them have two main parts. One part is called the stator. The stator is stationary; it does not move. The other part, the rotor, is mounted on bearings so it can rotate. The rotor shaft sticks out beyond the housing. For a generator, a prime mover is coupled to this shaft. For a motor, the rotor shaft is coupled to a mechanical load.

GENERATORS The input power to a generator is mechanical

power. If the output is a direct current, the generator is called a DC GENERATOR. If the output is an alternating current, it is known as an ALTERNATOR.

Prime movers apply mechanical power to turn the rotor. Water wheels, windmills, steam and hydro-turbines, diesel and jet engines, and hand cranks are all examples of prime movers.

To make a rotor turn, the prime mover applies TORQUE. Torque simply means turning force. For example, when you tighten a nut on a bolt, you apply torque with a wrench.

TORQUE The amount of torque applied to a shaft is proportional to t

wo things: 1. The amount of force applied. 2. The distance the force is applied away from the cente

r of the shaft. The torque, or turning force, is directly proportional to both

force and distance. The more force you apply, the greater the torque. Also, the longer the crank handle, the greater the torque. The equation is:

Torque (T) = force(F)×distance (d) In conventional units of measurement （计量单位） , force

is expressed in pounds. The abbreviation is lbf for POUNDS FORCE. One lbf is the amount of force that would be applied by the weight of one pound. Distance is measured in feet (ft.). Torque is expressed in pound forefeet (lbf-ft). Torque may also be expressed in ounce force-inches (ozf-in.).

MOTORS The power input to a motor is electrical. Voltage is applied t

o a motor’s terminals(终端） resulting in a current. The power output of a motor is mechanical. This power is transmitted by the rotor shaft as a torque. This torque tends to rotate a load, such as a fan or pump.

To drive a load at a particular speed, you need a certain amount of torque. If the motor’s output is large enough, the load will turn. If the motor’s torque output is too small, however, it will not drive the load. Torque requirement is one of the most important things to consider in selecting a motor.

As a motor drives a load, mechanical power is drawn from （从…中取得） the motor. The motor, in turn, draws electrical power from the source at the same rate.

Exercises

I. Translate the following expressions into Chinese or English.

与…成正比be directly proportional to与…成反比be inversely proportional to扭力torque force

转矩要求torque requirement磁场a magnetic field

电磁原则electromagnetic principle机械能mechanical energy

电能electrical energy交流，交流电alternating current (AC)

直流direct current (DC)

柴油发电机diesel engine generator柴油发电厂diesel power plant

原始能prime energy原动机prime mover曲柄箱crank case

手摇曲柄crank handle常用的计量单位conventional units of measure

通用标志conventional sign转子铁芯rotor core

转轴the rotor shaft

II. Fill in the following blanks with the words given. There are extra items.

1. The table clearly shows that less _____ will flow with more resistance at the same voltage. (current)

2. With the development of modern electrical engineering, power can be _____ to wherever it is needed. (transmitted)

3. Most people know that electricity standing still is no more useful than a _____ belt between a steam engine and a machine that needs to be driven. (stationary)

4. The government is _____ up the driving laws. (tightening)

5. The ailing man _____ two hours of work with one hour of rest. (alternated)

alternated mechanical be coupled to tightening magnetic stationaryconstruction current transmitted generate is proportional to mount

6. Few of them know the _____ of the machine. (construction)

7. Every wire carrying an electric current has a _____ field so long as the current flows. (magnetic)

8. The shaft of the turbine _____ the rotor of the generator. (is coupled to)

9. Mere _____ drill will not teach the student the differences between should and must. (mechanical)

10. The steam can _____ electricity by turning an electric generator. (generate)

alternated mechanical be coupled to tightening magnetic stationaryconstruction current transmitted generate is proportional to mount

III. Put the following sentences into English. 1. 交流电动机可分为同步电动机和异步电动机。 (inducti

on motor) Alternating motors can be classified into synchronous m

otors and induction motors. 2. 在选择电动机时必须考虑其转矩要求。 (torque require

ment) Torque requirement must be taken into consideration in

selecting a motor. 3. 线圈与磁场都在运动，但其速度各异。 (at the same r

ate) Both the wire and the field are in motion but not at the s

ame rate. 4.握手时用右手是一种惯例。 (conventional) It is conventional to shake hands using the right hand. 5. 原动机利用机械功率驱动转子。 (apply) Prime movers apply mechanical power to make the roto

r turn.

Skill of translation 3 、词类的转译

转译成动词名词、动名词 → 动词 The flow of electrons is from the negative zinc plat

e to the positive copper plate. 电子从负的锌极流向正的铜极。 I have no objection to your plan. 我不反对你们的计划。 Changing the resistance is a method of controlling

the flow of current.改变电阻是控制电路中电流流动的一种方法。

形容词 → 动词 If extremely low-cost power were ever to become a

vailable from large nuclear power plants, electrolytic hydrogen would become competitive.

如果能从大型核电站获得成本极低的电力，电解氢的竞争能力就会增强。

We should be aware of the whole circumstances. 我们应该摸清全部情况。

副词、介词 → 动词 He is for the plan, but I am against it. 他赞成这个计划，但我反对。

转译成名词 The rich shouldn’t look down upon the poor.富人不应看不起穷人。

4 、句子成份的转译主语的转换A. 转换为汉语的宾语

Modern industry requires that more and more natural gas be tapped.

现代工业要求开发越来越多的天然气。 Machines are found in every workshop. 在每个车间里都可以看到机器。

B.主语转换为汉语谓语。 There is a need for improvement in our experimental work. 我们的实验工作需要改进。 The statement of the first law of motion is as follows. 运动第一定律叙述如下。

C.主语转换为汉语定语 Warm-blooded animals have a constant body temperature. 热血动物的体温是恒定的。 The DC generator is the same in construction as the DC motor. 直流发电机的构造与直流电动机的相同。

D.主语转换为汉语状语 1960s saw the great advance in electronic industry with the em

ergence of the large-scale integrated circuits. 随着大规模集成电路的出现，电子工业在 20世纪 60年代取得了巨大的进展。

谓语的转换 A sketch serves to express one’s idea graphically.草图的作用就是把人们的想法用图表示出来。 The sun produces in three days more heat than all e

arth fuels could ever produce.太阳在三天内发出的热量比地球上所有燃料能发出的热量还要多。（定语）

For the first time in the annals of space, a piloted ship had succeeded in launching an earth satellite.

载人飞船成功地发射了一颗人造地球卫星，这在航空史上尚属首次。（状语）

宾语的转换 This sort of stone has a relative density of 2.7. 这种石头的相对密度是 2.7 Physical changes do not result in formation of new su

bstances, nor do they involve a change in composition.

物理变化不生成新物质，也不改变物质的成份。 The following provides a brief account of how the hu

man body is built. 下文简要说明人体是如何构成的。 China is experiencing rapid development of power in

dustry. 中国电力工业正在迅速发展。

定语的转换 Many factors enter into equipment reliability.涉及设备可靠性的因素很多。（谓语） Copper has very high conductivity.铜的导电率很高。（谓语） We should have a firm grasp of the fundamentals of

mechanics. 我们应牢固掌握力学的基本知识。（状语） These new computers are in wide use. 这些新计算机被广泛地使用。（状语）

状语的转换 In size and appearance Mercury is very much like our moon. 水星的大小和外观很像月亮。 Today, many different types of ATGMs exist throughout the worl

d. 目前，全世界拥有许多不同类型的反坦克导弹。 There are a great number of water and steam power plants in o

ur country. 我国有许多水力及火力发电厂。 Sodium is very active chemically. 钠的化学性质很活泼。 In steam locomotives, the spent steam is discharged direct into

the atmosphere. 蒸汽机车的废气直接排入大气中。 In his calculations he made few mistakes. 他在计算中的错误很少。

Assignment 翻译： In addition to the utilities, enterprises such as fac

tories, mines, and electric railways have several thousand power plants to generate electricity for their own needs. The total capacity for these plants in 1969 was estimated at 19 million kW. Many small, isolated plants are also installed in institutions, hotels, apartment houses, office buildings, amusement parks, etc. The capacities of these plants are not available, but they probably amount to only a few percent of the overall utility capacity.

Substation

The purpose of a substation is to transform the characteristic of the electrical energy supplied to some form suitable for use, as for example ,a conversion from alternating current to direct current for the use of city railway service ,or a change from one voltage to another ,or one frequency to another.

Their functions include:

Tap.—To be economical ,transmission of larger amounts of power over long distance must be done at voltages above 110,000 volts. Substation for supplying small amounts of power from such high-voltage lines are not satisfactory from the standpoint of operation and are also uneconomical .

It is ,therefore, common practice to install a few substation at advantageous points along the high-tension lines and step down the high-transmission voltage to a lower secondary-transmission voltage from which numerous small loads may be supplied.

Distribution.— Any substation that is used to transform electrical energy to a potential that is low enough for general distribution and utilization is a distributing substation .

Such a substation will generally receive its energy over a few comparatively high-tension lines and distribute it over a large number of low-voltage lines.

Industrial —When fairly large blocks of power are required by industrial plants, it often becomes necessary and advisable to install an individual substation to supply such a load directly from the main high-voltage line or secondary line of lower voltage .

Its simplest form would comprise only switching equipment, there being no voltage transformation.

In most cases a voltage transformation is probably needed; hence transformer equipment is included.

Sectionalizing.— In very long high-voltage large-capacity lines , particularly when several circuits are run in parallel , it is often necessary to split the lines into sections, in order that proper protection to the line and service can be obtained.

Such a substation is, therefore, helpful in sectionalizing damaged sections of a line, providing continuity of service.

Such a substation will generally comprise only switching equipment.

In long lines it may also serve to supply power-factor-correcting equipment.

Transmission-line Supply.— It is becoming more and more common to install the high-tension equipment of a power plant outdoors, the installation becoming nothing more than a step-up substation receiving its power at generator voltage , then stepping up its voltage and finally sending it out over high-voltage transmission lines.

Such a substation is nothing more than an outdoor distributing substation turned around, the voltage being stepped up of stepped down.

Power-factor Correction.— The voltage at the end of long lines tends to increase as the load supplied is decreased, while on the other hand it tends to decrease as the load is increased.

Owing to the inductance and capacity effects, this variation in voltage is accompanied by a wide variation in power factor of a line, it is necessary to use synchronous condensers at the end of the line.

To supply such a machine the transmission-line voltage must be stepped down, hence a power-factor-correcting substation will include switching equipment, transformer, and all equipment necessary for the operation of synchronous condensers .

Frequency changer.—To interconnect two systems of different frequencies it is absolutely necessary that frequency changers be used.

Invariably a station of this type will necessitate transformers to step down or step up the voltage supplied to or delivered from the frequency changer, since the highest voltage that is normally feasible for rotating machinery has been found to be about 13,200 volts.

Direct current for Light and Power.— There are still a few sections in some of out large cities which are supplied with direct-current three-wire systems. Such a supply is invariably obtained from synchronous converters.

There are also certain types of motor loads in industrial plants which require direct current; these are (as a general rule) supplied from rotary converters.

For electrolytic work, low-voltage direct current is absolutely essential, hence motor generators or rotary converters are also applicable.

1.Problem with the renewable resource is that they are not _____.

2.The beauty of sun power is _____________.

3.The battery is basically a device that converts chemical energy into electricity. It’s function is_____________________.

4.How to use solar paint to generate electricity ?