The Railway Technical Website > 자유게시판

• 목록
• 답변
• 글쓰기
• 게시판 리스트 옵션
  • 수정
  • 삭제

That is about its restrict for speed and has only spread over such a large area for historic causes. It may well use both DC (direct current) or AC (alternating present), the previous being, for a few years, easier for railway traction purposes, the latter being higher over long distances and cheaper to install however, till not too long ago, more difficult to control at prepare degree. It may be summarised simply as AC for long distance and DC for brief distance. Since the present might have been switched off to stop an arc or because of a brief circuit, it's important that the prepare does not join the useless part to the live part by passing over the gap and allowing its busline to bridge the gap. The other footwear on the same circuit have to be isolated whereas this is done, unless the current is switched off from the entire section - maybe disabling several other trains. It have to be protected, economical and consumer friendly.

The contact with the overhead wire is just not normally damaged but the third rail should be damaged at junctions to allow for the continuity of running rails. Both overhead techniques require not less than one collector hooked up to the prepare so it could actually always be in contact with the facility. As a pantograph passes alongside it, the wire may be seen to rise and fall. Many installations seen as we speak were first constructed greater than one hundred years ago, some when electric traction was barely out of its diapers, so to speak, and this has had an ideal affect on what's seen right now. There has to be a complete circuit, from the supply of the energy out to the consuming merchandise (mild bulb, cooking stove or practice) and back to the source, so a return conductor is required for our railway. An example of a bottom contact shoe as used on the Dockland Light Railway line in London is shown in Figure 3 and in the video (Figure 5). Some top contact programs have also used spring loading however they're mechanically tougher to regulate because of the hunting motion of the bogie and the chance that the shoes will get trapped below the pinnacle of the rail and switch it over.

Bottom contact is best - you possibly can cowl successfully many of the rail and it's protected from the worst of the chilly weather. Over long distances the unequal voltages can symbolize a security hazard. This would be prohibited in Britain as a result of inflexible safety strategy there. At various points along the line, there will likely be places the place trains can be temporarily isolated electrically from the provision system. Regardless of this, there may be problems. You will often see trains with just one pantograph but, on trains which use shoes, there are all the time a number of shoes. The contact wire tension can be within the region of two tonnes. Modern methods link the traction present standing to the signalling in order that a practice won't be allowed to proceed onto a lifeless part. The suspension methodology was originally simply a few slotted links to compensate for motion which allowed gravity to supply the necessary strain. It additionally implies that, if trains are stopped and have to be evacuated, the present must be turned off earlier than passengers can be allowed to wander the track. Transmission of energy is all the time along the monitor via an overhead wire or at ground level, using an additional, third rail laid close to the running rails.

Current is collected from overhead strains by pantographs. Pantographs are easy in terms of isolation - you simply lower the pan to lose the power supply to the vehicle. Isolation used to contain inserting a wood "paddle" between the shoe and the present rail and then tying the shoe up with a strap or rope. Modern shoe programs have distant lifting amenities. This is useful, because it helps the reader to get to grips with the modern stuff. When opened, they forestall a part of the line for being fed by the substation. Normally, each observe is fed in each direction in direction of the next substation. The return circuit is by way of the working rails again to the substation. The ability circuit on the train is completed by connecting the return to brushes rubbing on the axle ends. This has run in parallel with the event of power electronics and microprocessors. In cities corresponding to London, New York City and Boston, the same trains run beneath overhead wires for a part of the journey and use third rail for the remainder. AC programs all the time use overhead wires, DC can use either an overhead wire or a third rail; each are common.

If you liked this article and you would like to acquire more info pertaining to what is electric cable kindly visit our own web site.