英文文献翻译

1、英文文献翻译 the two lucable cranesgeneral descriptionthe 2 luffing cable cranes are destined for the construction of the three gorges dam in the valley of the yangtze river.the jobsite is situated near sandouping, yichang in the province hubei in the peoples republic of china.the cable cranes, representi

2、ng the main transport facility of a dam construction jobsite, have been designed for the purpose of transporting concrete, formwork items, concrete pre-fabitems, reinforcing material, building machinery and machine components such as penstocks, generators, lock gates, etc. . the cable cranes that wi

3、ll be used on the jobsite are of the luffing type, i. e. it has been given that name because for moving the track rope, the towers or masts one have to luff to the upstream or downstream direction.both the slewing masts of each single crane between which the track ropes are installed, are situated -

4、at an elevation of + 185 m on block 8 already concreted on the left bank and on the longitudinal coffer dam at the elevation of + 160 m.each mast has a height of 125 + 25 = 150m, and is firmly anchored by rear stay ropes in longitudinal direction. on their sides, the masts are held respectively move

5、d by 6-strand luffing ropes actuated by winches.the spans are:rear stay ropes on the left bank approx. 270mrear stay ropes on the right bank approx. 604.5m.track ropes: approx. 1416mthe machine houses for the winches of the cranes are arranged on the foot of the masts.in the machine houses on the fo

6、ot of the head towers are arranged the winches for hoisting crab traversing and mast luffing.in the machine houses on the foot of the tail towers are only situated the winches for mast luffing . this machine houses are therefore called luffing winch house .the control electronics are each located in

7、 separate rooms, for thus avoiding any problems as might occur by dust or also temperature variations.there are three possibilities to control the winches.normally the crane is controlled by the drivers cabin that is movable between the machine side and the counter side on a long cable.the second wa

8、y is to control the cable crane by a -wireless portable control unit. for each crane there is one mobile unit.the third possibility to control the winches is the local control device nearby the machines for the hoist, crab traversing and luffing systems . the local control device is for purpose of e

9、asy adjustment and repairing.because of the local situation, there are certain areas of the working field with obstacles. these areas are locked by the programmable computer control system.for the control systems see also the electrical documents of abb company.the crab traversing winch is driven by

10、 a dc-motor that allows for an infinitely variable speed regulation. for physics reasons he acceleration shouldnt be much beyond 0. 75 m/s2 .thereof result acceleration and braking times of approx. 10 seconds (braking torque about 6000 nm) ; respective path is approx. 37:5m. with commissioning opera

11、tions the mechanicalbrake shall be set in a way that the loaded crab will come to be stopped after at the latest 12 seconds (braking torque approx. 6000 nm). because of the varying loads will result otherwise with merely mechanical braking (emergency) shorter braking times. normally the torque havin

12、g been generated by the motor is transmitted over a 2-groove drive pulley to the crab traversing rope. here one has to check periodically for ensuring-an uniform running in the two grooves (see chapter maintenance). between the two grooves the crab traversing rope is led over the return pulley; at t

13、he shaft of which is also fitted :the screw-type limit switch and the position indicator, just also the tachometers for measuring the speed and for control of a possible over speed. although the screw-type limit switch and the position indicator are driven by the non-driven return pulley, it is unav

14、oidable that after a duration of operation occurs a certain miss-indication, so that the correction will have to be made (see chapter traversing limit switches and position indicators).for safety reasons have been installed, however, at the first and at the last rope carrier additional limit switche

15、s for monitoring the crab speed. since these limit switches cannot shift out of their set position, the signal is absolute. finally the crab traversing is then stopped by a lever limit switch attached at each end of the track rope.the tachometer for monitoring a possibly occurring over speed disconn

16、ects the crab traversing gear at 115% rated speed by emergency off.for providing the operation and maintenance team with information concerning the plant output, the crab traversing gear is equipped with an operation hour s counter and a cycle counter. here the operation hours counter is detecting t

17、he time in which the crab traversing motor is working, and the cycle counter the number of traversing runs. therefore the cycle counter is set in a way that after each motor operation time of about 10 seconds in one direction another half cycle is counted up. in case the travel is interrupted and co

18、ntinued, thereafter in the same direction no new half cycle will be added. in case the direction of travel is reversed, however, and then will result after another 10 seconds a new half cycle.the cycle counter shall be a help for the maintenance team to get a better idea about the working life of va

19、rious wearing items such as trolley traversing rope, hoisting rope, rope carriers, drive pulley lining, etc. . it is necessary that with the exchange of these items are always read at the cycle counter the resp. working cycles and that the results will be registered.as an additional maintenance help

20、 a lubricants tank is mounted to the traversing winch for lubrication of the crab traversing rope (please refer also to chapter general maintenance instructions ) .traversing limit switches and position indicatorsas mentioned in the previous chapter the position indicator and the traversing limit sw

21、itch (a screw-t)pe limit switch) are arranged on the shaft of the return pulley, from which they can both be separated by a magnetic tooth coupling. with erection the traversing limit switch is set in a way, that the crab stops travel 130m before reaching the machine side, or resp. 110m before the c

22、ounter side. the position indicator should then show the corresponding value.during operation the crab is automatically braked down electrically to v = 0 m/s, when one of the two end positions is reached. on the remaining track rope length travel is then only possible, when the by-pass button is dep

23、ressed. by depressing the by-pass button the travel speed is also limited to v 20% of v rated. running in opposite direction within ns nange, there is no speed limitation.in order to ensure principally a reduction of the crab speed, the plant has been equipped with two additional stationary monitori

24、ng limit switches. these are arranged on always the first and the last rope carrier. as these are in parallel connection with the screw-type limit switch, they also cause a reduction of the crab traversing speed to v = 0 m/s by electrical breaking. to continue the travel to the end of the track rope

25、 is only possible by depressing the by-pass button.the crab traversing is finally stopped electrically by each one limit switch at the end of the track rope.for being capable on principle to take into consideration further obstacles in the travel area, the screw-type limit switch has been equipped w

26、ith further contacts.by the unavoidable slip between return pulley and crab traversing rope, and by the retensioning of the crab traversing rope, a correction of the screw-type limit switch and the position indicator will become necessary. this correction should be made at least once a day with star

27、t of the new shift. for this purpose the crab must be run to a position that is known to the crane driver and from which is known the exact distance up to the respective end of the track rope (as reference position would be suitable a rope carrier or the concrete platform) . incase, at that position

28、 of the crab, the value shown for the position of the crab is not in accordancp with the actual distance, then the screw-type limit switch and the position indicator must be corrected.for this purpose the crab must be run into a position, where the position indicator is showing the set distance ( e.

29、 g. at the first rope carrier 50 m) . as soon as this figure is appearing on the display, crab traversing must be interrupted and the synchronous button will separate the return pulley from the screw-type limit switch and the position indicator and will limit the crab traversing speed to v 20 % of v

30、 rated. the synchronous button must be depressed during the whole synchronization procedure. the crab is then run to the reference point that has been set to the display (e.g. the first rope carrier)mainteoanoebeside the general maintenance and inspection work, and as is further described under the

31、chapter general maintenance instructions and lubrication, the owner should take care for a uniform running of the ropes in the becorit lining. as soon as irregularities will occur, these can be eliminated by a correction of the alignment of the drive pulley and of the return pulley. for this purpose

32、 setting screws are fitted to the pillow blocks of the drive pulley and of the return pulley. by the clamping set incorporated in the return pulley, the latter can also be shifted axially.the drive pulley of the crab-traversing winch is designed as 2-groove drive pulley lined with becorit : dependin

33、g on the varying rope tension of the crab traversing rope in the two rope grooves and the different rope slip there from results a different wearing of becorit lining in the two grooves. a different groove depth means also a different circumferential speed and this results forcibly in an increased r

34、ope slip and therefore in a heavier. wearing of the lining.therefore the drive pulley grooves must be checked frequently for their depth (by means of gauge). with a depth difference of 2 mm one groove is to be turned until the two grooves have again the same depth. turning speed for cutting 2 to 4 m

35、/ sec.the becorit lining should be replaced as soon as the remaining thickness has come down to approx. 20 nun. this corresponds to a total groove depth of 40mm at a lining thickness of 60 mm. 双塔俯仰式缆机概述双塔俯仰式缆机是为长江三峡大坝建设设计的，工地位于中华人民共和国湖北省宜昌三斗坪附近。双塔俯仰式缆机作为大坝建设工地的主要运输设备，设计的用途是运输混凝土，模板，混凝土预制件，钢筋，施工机械和机械

36、部件，如压力水管，发电机，闸门等。将要在工地使用的缆索起重机属仰俯式，也就是说，它之所以被称为仰俯式是因为移动跑索时，起重塔或起重桅杆必须向上游或下游仰俯。缆机的两个转动起重塔杆，中间安装跑索，布置在左岸已浇筑的标高为185m的8号坝块上和标高为160m的纵向围堰上。各转动起重塔杆高为150m,用后置固定钢索纵向固定，在杆两侧分别由绞盘驱动的六股起落索固定和移动。跨度：左岸后置固定缆索约为270m.右岸后置固定缆索约为640.5m.跑索约为1416m.绞盘的机房设置在起重塔杆脚下。首塔脚下的机房内装有控制缆车横向移动和起重塔杆仰俯用的绞盘。尾塔脚下的机房内仅装有控制起重塔杆仰俯用的绞盘。这些机

37、房因此称为仰俯绞盘机房。电子控制设备分别安装在单独的机房里，因为这样能避免由于灰尘或温度变化可能引起的问题。有三种可能的方法来控制绞盘。缆机通常由驾驶室控制，驾驶室可在一根长缆索上来回机侧和计数器侧之间。第二种方法是用无线移动遥控机来控制缆机。每台缆机都配有一部移动遥控机。第三种方法是在机构附近来控制起重，缆车横移和仰俯，就是控制装置便于调节和修理。由于当地的情况，在施工现场的某些区域有障碍物。这些区域被可编程的计算机控制系统锁定。缆车横移绞盘由直流马达驱动，可无级调速。由于物理原因，加速不应大幅度超过0.75m/s.因此产生的加速度和制动时间约为l os,各自的路径约为37.5m.试运行时对

38、机械制动的设定应保证载重的吊车最迟在12s后停止，另外用机械制动时，由于制动负荷的不同还会导致更短的制动时间。通常，马达的转矩通过双槽驱动滑轮传递给缆车横移索，故必须定期检查以确保两槽内的钢索同步运行。在两槽之间，缆车横移缆索被引导到返程滑轮上，在返程滑轮的轴上装有螺杆型限位开关和位置指示器，另外还装有测量速度和控制可能发生的超速用的转速器。尽管螺杆型限位开关和位置指示器由从动返程滑轮带动，但不可避免会在运行一段时间后会出现指示误差，因此必须进行校正然而，为安全起见，在第一个和最后一个横移缆索支架处还另外装了监控吊车速度的限位开关。由于这些开关不可能从设定的位置上移走，故信号是绝对的。最后，装在跑索两端的杠杆限位开关还可阻止吊车横移。监控可能发生的超速用的转速计可通过“事故停车”以115%的额定速度断开缆车横移机构。为了给运行和维护人员提供关于设备工作量的信息，缆车横移齿轮配有运行小时计数器和工作循环计数器。运行小时计数器监测缆车横移马达目前工作的时间，工作循环计数器监测横移运行的次数。因此，循环计数器设置位马达在同一方向运行约l os后为一次，并将余下的另一半程计算在内。如果