Transcript TORQUE

《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：
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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：
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直流(direct current)电机
交流(alternating current)电机
 按速度分：
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直流电机；变压器；异步(asynchronous)电机；同步
(synchronous)电机
电机的两个基本原理：
 1. A moving charge in a magnetic field
experiences a force.
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 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
produces 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.
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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 words
1. 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
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2. flux
 n.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
everything 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。
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流出
 vt.使熔融, 用焊剂处理
 vi.熔化,
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3. motion
 n.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。
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 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。
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4. stator
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rotor
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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
（电机的）转子
（直升机的）水平旋翼
bearing
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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：
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举止，风度：一个人的行为方式
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Those issues have no bearing on our situation.
那些问题与我们的情况无关
“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
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5. stationary adj.
 静止的
Not moving.
 不能被移动的；固定的 Not capable of being moved;
fixed.
 不变的 Unchanging:
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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
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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。
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11. alternator
 交流发电机
 three-phase alternator三相交流发电机
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AC = alternating current
DC = direct current
director
主管, 导演, (机关)首长, (团体)理事, (公司)董事,
指挥仪, 控制器
 n.主任,
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12. windmill
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n.风车, 风车房, 旋转玩具
vt.使旋转
vi.作风车般旋转
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13. hydro-turbine
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n.柴油（发动）机
15. crank
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n.水轮机
14. diesel
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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
adj.脾气暴燥的, 易怒的
n.[机]曲柄, 奇想
vt.[机]装曲柄
16. torque
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n.转矩；扭矩
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17. tighten
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vt.使变紧，使绷紧
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tight
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tighten one's belt
束紧腰带, 节约度日
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
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n.伤别；别离的痛苦,扳钳, 扳手
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the wrench of leaving home
离家的悲痛
vt.扭伤
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to wrench one's ankle
扭伤某人的脚脖子
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19. proportional
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比例上的
成比例的；相称的
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20. equation n.
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【数学】等式,方程式【化学】化学方程式
equations set 方程组
21. conventional adj.
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因袭的；传统的，习惯的
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conventional weapon 常规武器
22. abbreviation
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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
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Punishment ought to be proportional to the crime.
惩罚应该与所犯的罪相应
缩写，缩写式
23. requirement

需要，要求
Phrases and Expressions
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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
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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.
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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.
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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 hydroturbines, 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.
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TORQUE
The amount of torque applied to a shaft is proportional to
two things:
 1. The amount of force applied.
 2. The distance the force is applied away from the
center 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.).
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MOTORS
The power input to a motor is electrical. Voltage is applied
to 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.
direct current (DC)
直流
alternating current (AC)
交流，交流电
electrical energy
电能
mechanical energy
机械能
electromagnetic principle
电磁原则
a magnetic field
磁场
torque requirement
转矩要求
torque force
扭力
be inversely proportional to
与…成反比
be directly proportional to
与…成正比
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the rotor shaft
rotor core
conventional sign
conventional units of measure
crank handle
crank case
prime mover
prime energy
diesel power plant
diesel engine generator
转轴
转子铁芯
通用标志
常用的计量单位
手摇曲柄
曲柄箱
原动机
原始能
柴油发电厂
柴油发电机

II. Fill in the following blanks with the words given.
There are extra items.
alternated mechanical be coupled to tightening magnetic stationary
construction current transmitted generate is proportional to mount
 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 stationary
construction 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)

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。
(induction motor)
 Alternating motors can be classified into synchronous
motors and induction motors.
 2.在选择电动机时必须考虑其转矩要求。(torque
requirement)
 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
rate)
 Both the wire and the field are in motion but not at the
same 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
rotor turn.
Skill of translation
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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
plate 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
available 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。
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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。
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 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
emergence 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
earth 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）
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 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
substances, 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
human body is built.
 下文简要说明人体是如何构成的。
 China is experiencing rapid development of power
industry.
 中国电力工业正在迅速发展。
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 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）
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 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
world.
 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
our 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
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翻译：
In addition to the utilities, enterprises such as
factories, 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
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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:
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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 hightransmission voltage to a lower secondarytransmission voltage from which numerous small
loads may be supplied.
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Distribution.— Any substation that is used to
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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 lowvoltage lines.
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Industrial —When fairly large blocks of power
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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.
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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 powerfactor-correcting equipment.
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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.
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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 powerfactor-correcting substation will include switching
equipment, transformer, and all equipment
necessary for the operation of synchronous
condensers .
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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.
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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 ?
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