电力专业英语第十三讲

1、山东交通学院电气系张建军 词汇abnormal bn:mla. 反常的, 不正常的变态的，畸形的; hexagonal heksnl a. 六角(边)形的cartridge k:trd n. 拾音器心座 子弹，弹药筒; 笔芯，墨盒; 暗盒，胶卷盒; 录音带盒;quench kwent v. 淬熄；扑灭 解（渴）; 终止（某事物）; 将（热物体）放入水中急速冷却;ferrule ferln. 套圈；箍 金属箍，金属环circuit breaker 断路器 课文内容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、设备和仪器are rated 被规定额定值according to the normal value of voltage which can be applied to them 根据施加给它们的正常电压值and the current which they can safely carry

3、. 和它们所能安全输送的电流值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 假如超过安全值的电压or if hig

4、her than rated current were to flow the conductor or piece of equipment或者有超过额定值的电流流过导体或一个设备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.将会导致人员面临危险的情况To protect conductors and equipment against abnormal operating conditions 为了防止导体和设备出现异常工作状况and their consequences和它们所带来的后果These devices include fuses, circuit breakers and relays and are commonly called “protectiv

6、e devices”. These devices include fuses, circuit breakers and relays 这些装置包括熔断器、断路器和继电器protective devices保护装置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 “link” 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它将传导电路（和熔断器）的额定

8、电流called a “link” 称为熔体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大小和类型to provide overload protection for both circuits and apparatus对电路和设备提供过载保护Enclosed

10、 fuses封闭式熔断器range in capacity up to 600 amps at 250 and 600 volts.在250和600伏时的断流容量可达到600安培but will blow in from 1 to 5 minutes 但是会在1至5分钟内烧断if current exceeds a 15 per cent rise over rated capacity. 如果电流超过额定值得15% rated capacity额定容量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插入式熔断器screw-in type fuses螺旋式熔断器The Edison-base plug fuse插座式保险丝as a branch circuit protector in residential electrical systems做为住宅电气系统的支路保护 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年间，爱迪生设计了电灯插座、电钮、保险丝、电流切断器、电表、挂灯，还设计了主线和支线系统，又制成了当时世界上容量最大的发电机，并在纽约建立第一座发电厂，开辟了第一个民用照明系统。consists of a wire or strip of fusible metal 包括一根金属熔丝或熔片 porcelain case陶瓷外壳mica disk云母片The screw base corresponds to the base on a standard med

14、iumbase incandescent lamp 螺旋底座与标准白炽灯的底座一致incandescent lamp白炽灯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有一个六角形的管帽through which the mica shows通过它可以看到云母or they may have an hexagonal recess or projection in the top或者它们在顶部有一个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在顶部有一个圆窗 to make the lower rated fuses easily distinguishable from the higher rated fuses使低额定值熔断器区别于高额定值熔断器to minimize accidental interchange of the fuses. 使偶然互换熔断器的概率最小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保险丝座;Plug fuses and fuse holders classified as type S S型插入

18、式熔断器和熔断器底座tamper resisting防误用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这样安排消除了电路中熔断器熔点过高可能带来的危险in which the current may exceed the rating of the circuit conductor and load devices but does not exceed the rating of the fuse在这里电流或许超过了电路中导体和负载设备的额定值，但没超过熔断器的额定值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防误用熔断器得到了广泛的使用The tamper-resi

21、sting characteristic is accomplished by using a special fuse construction and adapter通过使用特殊的熔断器结构和适配器来实现防误用特性熔断器的适配器包括基座,微动指示开关和散热 器等The adapter is first screwed on the fuse base.适配器首先用螺丝拧到熔断器底座上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 然后将其（组合）旋入Edison-base

23、 cutout 螺旋式熔断器或底座if the fuse should then be removed from the holder如果要从底座中取出熔体and a Type S fuse of the wrong group rating cannot be inserted 并且S 型熔断器中额定值有误的也不能插入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 电路的异常运行状况Persist坚持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.这些是一次性熔断器except for the base construction除了底座结构Edison plug fuse receptacle螺旋式熔断器底座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 起动冲击电流

28、If, however,然而the high current should persist past the high current should persist past the delay time of the fuse这个大电流持续时间超过了熔断器的延时时间 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