地铁客运服务英语课件第六单元教材课件moban.ppt

1、Part BPart BPart EPart EPart DPart DPart APart APart CPart CUnit 6 Power Supply System地铁供电系统地铁供电系统Part BPart BPart EPart EPart DPart DPart APart APart CPart CTranslate the following words into English:低低低低压压配配配配电盘电盘 _综综合合合合监监控系控系控系控系统统 _ _ 通信系通信系通信系通信系统统_自自自自动动售售售售检检票系票系票系票系统统_Part BPart BPart EPart

2、 EPart DPart DPart APart APart CPart C(Brown is a Canadian Engineer.He is having a conversation with a subway staff member John.)Brown:How many components does power supply system have in the subway?John :Basically we have city electricity,LV distributor,UPS,computer controlled Smart UPS and subsyst

3、ems.Brown:Why does the signal system have two power supplies?John :This is because signal system are the lifeline of subway operation.Out of power may cause huge accidents,casualties and economic loss.Two power supplies can ensure its reliable running.Brown:Well,LV distributor has two power supplies

4、,is it because of the same reason?John :Absolutely.Brown:What is UPS?John :The full name of UPS is Uninterruptible Power Supply which improves the reliabilities of subway power supplies.Brown:What is the mode of power supply for the Metro?John :Usually there are two modes,third rail and overhead wir

5、es.It is different from city to city.Brown:I see.I have learned a lot today.Part BPart BPart EPart EPart DPart DPart APart APart CPart CPart BPart BPart EPart EPart DPart DPart APart APart CPart CPart C TextPart C Text Although the initial lines of what became the London Underground used steam engin

6、es,most metro trains,both now and historically,are electric multiple units,with steel wheels running on two steel rails.Power for the trains,referred to as traction power,is commonly supplied by means of a single live third rail(as in New York)at 600 to 750 volts,but some systems use two live rails(

7、notably London)and thus eliminate the return current from the running rails.Overhead wires,allowing higher voltages,are more likely to be used on metro systems without much length in tunnel,as in Amsterdam;but they also occur on some that are underground,as in Madrid.Bostons Green Line trains derive

8、 power from an overhead wire,both while traveling in a tunnel in the central city and at street level in the suburban areas.Systems generally use DC power rather than AC,even though this requires large rectifiers for the power supply.DC motors were formerly more efficient for railway applications,an

9、d once a DC system is in place,converting it to AC is generally considered too large a project to complete.Part BPart BPart EPart EPart DPart DPart APart APart CPart CPart BPart BPart EPart EPart DPart DPart APart APart CPart Cn n1.Please list two modes of power supply for 1.Please list two modes of

10、 power supply for metro.metro.n nthird rail and overhead wires third rail and overhead wires n n2.Please list the name of each part of the 2.Please list the name of each part of the power supply system.power supply system.n nThird rail:a live third rail,operational rail Third rail:a live third rail,

11、operational rail overhead wires:wires,pantograph overhead wires:wires,pantograph n n3.Whats the characteristic of power supply 3.Whats the characteristic of power supply system?system?n nTraction power is supplied by Traction power is supplied by meanismeanis of a of a single live third rail or overhead wires.single live third rail or overhead wires.Part BPart BPart EPart EPart DPart DPart APart APart CPart C