電力專業(yè)英語(yǔ)第十三講

1、山東交通學(xué)院電氣系張建軍 詞匯abnormal bn:mla. 反常的, 不正常的變態(tài)的，畸形的; hexagonal heksnl a. 六角(邊)形的cartridge k:trd n. 拾音器心座 子彈，彈藥筒; 筆芯，墨盒; 暗盒，膠卷盒; 錄音帶盒;quench kwent v. 淬熄；撲滅 解（渴）; 終止（某事物）; 將（熱物體）放入水中急速冷卻;ferrule ferln. 套圈；箍 金屬箍，金屬環(huán)circuit breaker 斷路器 課文內(nèi)容Electrical wires, cables, devices, equipment and apparatus are rate

2、d according to the normal value of voltage which can be applied to them and the current which they can safely carry. devices, equipment and apparatus 元件、設(shè)備和儀器are rated 被規(guī)定額定值according to the normal value of voltage which can be applied to them 根據(jù)施加給它們的正常電壓值and the current which they can safely carry

3、. 和它們所能安全輸送的電流值If other than the safe value of voltage were applied to a conductor or piece of equipment, or if higher than rated current were to flow, the conductor or piece of equipment would be seriously damaged or completely destroyed1. If other than the safe value of voltage 假如超過(guò)安全值的電壓or if hig

4、her than rated current were to flow the conductor or piece of equipment或者有超過(guò)額定值的電流流過(guò)導(dǎo)體或一個(gè)設(shè)備In addition, a general condition of hazard to personnel would result. To protect conductors and equipment against abnormal operating conditions and their consequences, a special group of devices are used in el

5、ectrical systems. a general condition of hazard to personnel would result.將會(huì)導(dǎo)致人員面臨危險(xiǎn)的情況To protect conductors and equipment against abnormal operating conditions 為了防止導(dǎo)體和設(shè)備出現(xiàn)異常工作狀況and their consequences和它們所帶來(lái)的后果These devices include fuses, circuit breakers and relays and are commonly called “protectiv

6、e devices”. These devices include fuses, circuit breakers and relays 這些裝置包括熔斷器、斷路器和繼電器protective devices保護(hù)裝置Fuses: A fuse is the simplest, best known and most widely used device for opening an electrical circuit when excessive current flows due to overload or short circuit. Basically, a fuse is a se

7、ries circuit device which will conduct the current for which the circuit（and the fuse） is rated；but it has an internal element, called a “l(fā)ink” which will melt and open the circuit when excessive current flows.which will conduct the current for which the circuit（and the fuse） is rated它將傳導(dǎo)電路（和熔斷器）的額定

8、電流called a “l(fā)ink” 稱為熔體There are many types and sizes of fuses used to provide overload protection for both circuits and apparatus. Enclosed fuses range in capacity up to 600 amps at 250 and 600 volts. Fuses for high voltage applications（above 600 volts）are available with current capacities up to 400

9、 amps and voltage ratings to 132 000 volts. Fuses will carry their maximum rated current continuously but will blow in from 1 to 5 minutes if current exceeds a 15 per cent rise over rated capacity. types and sizes大小和類型to provide overload protection for both circuits and apparatus對(duì)電路和設(shè)備提供過(guò)載保護(hù)Enclosed

10、 fuses封閉式熔斷器range in capacity up to 600 amps at 250 and 600 volts.在250和600伏時(shí)的斷流容量可達(dá)到600安培but will blow in from 1 to 5 minutes 但是會(huì)在1至5分鐘內(nèi)燒斷if current exceeds a 15 per cent rise over rated capacity. 如果電流超過(guò)額定值得15% rated capacity額定容量Plug Fuses: These are screw-in type fuses. The Edison-base plug fuse is

11、 familiar to everyone from its wide application as a branch circuit protector in residential electrical systems. Plug Fuses插入式熔斷器screw-in type fuses螺旋式熔斷器The Edison-base plug fuse插座式保險(xiǎn)絲as a branch circuit protector in residential electrical systems做為住宅電氣系統(tǒng)的支路保護(hù) An Edison-base plug fuse consists of a

12、 wire or strip of fusible metal in a small porcelain case with a mica disk set in the top making the fuse link visible. The screw base corresponds to the base on a standard mediumbase incandescent lamp. These fuses are confined to use on circuits rated at a maximum of 125 volts. They are made in var

13、ious current ratings：3, 6, 10, 12, 15, 20, 25 and 30 amps.1880年至1882年間，愛(ài)迪生設(shè)計(jì)了電燈插座、電鈕、保險(xiǎn)絲、電流切斷器、電表、掛燈，還設(shè)計(jì)了主線和支線系統(tǒng)，又制成了當(dāng)時(shí)世界上容量最大的發(fā)電機(jī)，并在紐約建立第一座發(fā)電廠，開(kāi)辟了第一個(gè)民用照明系統(tǒng)。consists of a wire or strip of fusible metal 包括一根金屬熔絲或熔片 porcelain case陶瓷外殼mica disk云母片The screw base corresponds to the base on a standard med

14、iumbase incandescent lamp 螺旋底座與標(biāo)準(zhǔn)白熾燈的底座一致incandescent lamp白熾燈Those fuses rated at 15 amps or less have an hexagonal opening in the cap, through which the mica shows, or they may have an hexagonal recess or projection in the top, or the top itself may be hexagonal in form. have an hexagonal opening i

15、n the cap有一個(gè)六角形的管帽through which the mica shows通過(guò)它可以看到云母or they may have an hexagonal recess or projection in the top或者它們?cè)陧敳坑幸粋€(gè)六角形的凹陷或凸起Those fuses rated from 16 to 30 amps have a round window in the top. The purpose of this is to make the lower rated fuses easily distinguishable from the higher rate

16、d fuses to minimize accidental interchange of the fuses. have a round window in the top在頂部有一個(gè)圓窗 to make the lower rated fuses easily distinguishable from the higher rated fuses使低額定值熔斷器區(qū)別于高額定值熔斷器to minimize accidental interchange of the fuses. 使偶然互換熔斷器的概率最小Plug fuses and fuse holders classified as ty

17、pe S are similar in general construction to the Edison-base plug fuse and its holder. Type s fuses, however, are tamper resisting, i. e., fuses of the 0 to 15 amp sizes cannot be interchanged with fuses of the 16 to 30-amp sizes. fuse holders保險(xiǎn)絲座;Plug fuses and fuse holders classified as type S S型插入

18、式熔斷器和熔斷器底座tamper resisting防誤用This arrangement eliminates the possible hazards of overfused (too large a fuse) circuits, in which the current may exceed the rating of the circuit conductor and load devices but does not exceed the rating of the fuse. This arrangement eliminates the possible hazards of

19、 overfused (too large a fuse) circuits這樣安排消除了電路中熔斷器熔點(diǎn)過(guò)高可能帶來(lái)的危險(xiǎn)in which the current may exceed the rating of the circuit conductor and load devices but does not exceed the rating of the fuse在這里電流或許超過(guò)了電路中導(dǎo)體和負(fù)載設(shè)備的額定值，但沒(méi)超過(guò)熔斷器的額定值The use of tamper-resisting plug fuses is widely recommended. These fuses a

20、re available with the same ratings as Edison base plug fuses. The tamper-resisting characteristic is accomplished by using a special fuse construction and adapter. The adapter is first screwed on the fuse base. The use of tamper-resisting plug fuses is widely recommended防誤用熔斷器得到了廣泛的使用The tamper-resi

21、sting characteristic is accomplished by using a special fuse construction and adapter通過(guò)使用特殊的熔斷器結(jié)構(gòu)和適配器來(lái)實(shí)現(xiàn)防誤用特性熔斷器的適配器包括基座,微動(dòng)指示開(kāi)關(guān)和散熱 器等The adapter is first screwed on the fuse base.適配器首先用螺絲擰到熔斷器底座上Then the combination is screwed into a regular Edison-base cutout or holder. if the fuse should then be r

22、emoved from the holder, the adapter stays in the holder, and only the same size Type S fuse can be replaced in the holder. An ordinary plug fuse cannot be inserted in the holder, and a Type S fuse of the wrong group rating cannot be inserted.Then the combination is screwed into 然后將其（組合）旋入Edison-base

23、 cutout 螺旋式熔斷器或底座if the fuse should then be removed from the holder如果要從底座中取出熔體and a Type S fuse of the wrong group rating cannot be inserted 并且S 型熔斷器中額定值有誤的也不能插入Times-delay plug fuses are fuses which allow the abnormal circuit operating condition to persist for a longer time before blowing than ordi

24、nary fuses. Also called “timelag” fuses, they are available in regular Edison-base type plug and tamper resisting screw base up to 30 amps. abnormal circuit operating condition 電路的異常運(yùn)行狀況Persist堅(jiān)持These are one-time（non-renewable）fuses. The Edison-base type and tamper-resting base type are identical e

25、xcept for the base construction. Again the tamper-resisting type needs an adapter before it can be screwed into an Edison plug fuse receptacle. Adapters are made in three common sizes: a 15-amp adapter which will take any size fuse up to 15 amps; a 20-amp adapter for a 20-amp fuse；and a 30-amp adapt

26、er a 20-, 25-, or 30-amp fuse. These are one-time（non-renewable）fuses.這些是一次性熔斷器except for the base construction除了底座結(jié)構(gòu)Edison plug fuse receptacle螺旋式熔斷器底座The time-delay type fuse is widely used on motor circuits in which the starting current inrush is much higher than the continuous current. The time-

27、lag fuse will not open on the short duration of high starting current. If, however, the high current should persist past the high current should persist past the delay time of the fuse, it will blow just as if a short circuit or heavy overload current had developed.the starting current inrush 起動(dòng)沖擊電流

28、If, however,然而the high current should persist past the high current should persist past the delay time of the fuse這個(gè)大電流持續(xù)時(shí)間超過(guò)了熔斷器的延時(shí)時(shí)間 Cartridge Fuses: A typical cartridge fuse consists of a tube of stiff, treated paper, fiber or some similar material, with the fuse element within the tube. A contact piece of some type is mounted on each end of the tube. The fuse