352履帶拖拉機(jī)(中央傳動(dòng)及轉(zhuǎn)向離合器設(shè)計(jì))【含CAD圖紙】
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Introduction to Locmotive
A locomotive is a railway vehicle that provides the motive power for a train,and has nohy detached from their trains, are known as power cars.
Traditionally,locomotive hual their trains. Increasingly common these days in passenger service is push-pull operation,where the locomotive push the trains in one direction and are controled from a control cab at the opposite end of the train in the other.
Beniefits of locomotives
There are many reasons why the motive power for trains has been traditonally isolated in a locmotive,rather than is self-propelled vehicles.these include:
Ease of maintenance – it is easier to maintain one locomotive than many self-propelled cars.
Safety – it is often safer to locate the train’s power system away from passenger. This was particularly the case for the steam locomtive,but still has some relevance.
Easy replacement of motive power – should the locomotive break down, it is easy to replace it with a new one . Failure of the motive power unit does not require taking the whoole train out of service.
Efficiency – idle trains do not waste expensive motive power resources. Separate locomotives mean that the costly motive power assets can be moved around as needed.
Obsolescence cycles – separating the motive power from the payload-hauling cars means that either can be replaced without affecting the other. At some times, locomotive have become obsolete when their cars are not, or vice versa..
Electric Locomotives
The electric locomotive is supplied externally with electric power, either through an overhead pickup or through a third-rail. While the cost of electrifying track is rather high, electric trains and locomotives are significantly cheaper to run than diesel ones, and are capable of superior acceleration as well as regenerative braking, making them ideal for passenger service in densely populated areas. Almost all high speed train systems(e.g..IEC,TGV, bullet train) use electric power, because the power needed for such performance is not easily carried on board. Fot example the most powerfu electric locomotives that are used today on the channel tunnel freight services use 7Mwatts of power.
The first known electric locomotive was buit by a Scotsman, Roert Davidson of Aberdeen in 1837 and was powered by galvanic cells.
Modern electric locomotive range from small battery-powered machines for use in mines to large main-line locomotives of 6,000 horsepower(4.5MW) or more.
In reality most modern locomotives are electricaly driven. Pure electric locomotives take their electrical supply from an external source while diesel-electric locomotives carry their own generating station.
Main line electric locomotives first appeared at the beginning of the 20th century.The reason for their introduction was the problem of smoke, especially in tunnlels caused by steam locomotives. In the UK this was the London underground system while in the USA, it was under river tunnles and needs to eliminate smoke in built up areas.
Early electric locomotives all relied on external power sourcing. Once up and running they tend to be reliable and efficint, but the supply infrastructure is a large capital expense that does require ongoing maintenance. For this reason only heavily used lines could justify electrification. For suburban lines the reduction in pollution from steam locomotives was a benefit all were aware ofl
The world speed record for a wheeled train was set in 1990 ba a French TGV which reached a speed of 515.3km/h (320mph).
While recently designed electrififed railway systems invariably operate on alternating current, many existing direct current sytems are still in use –e.g. in South Africa,Spain,and the United Kingdom(750v and 1500v); Netherlands(1500v); Belgiu, Italy, Poland (3000 v), and the cites of Mumbia and Chicagio (which will be switched to AC by 2025).
Early locomotives came in a variety of forms. Generally they were designed to run off the supplied current. so locomotives with a direct current (DC) supply had DC motors while a alterntating current(AC) supplied locomotives with AC motors. AC can be either single or three phase. While the former requies two wire supply, one overhead the other being the track, three phase require three supply wire.Three phase locomotives therefore had two overhead supplies,the track being the third.
DC supplies were either overhead or by means of a track level supply, commonly called the third rail.
AC traction motors tended to be smaller than DC motors. This often meant electric locomotives with steam engine type cranks. DC motors could be smaller and set up to drive the axles.usually through a gear ,but in some early examples by being part of the axle. Even so, some notable DC electric locomotives had large DC motors driving large driving wheels.
One possibility with electric locomotives is that the motor can be used as a generator during braking, feeding electricity back into the supply system; this is called regenerative barking. This is not a new idea, it was one reason for the adoption by some railways of 3 phase AC suppies. Especially in mountainous aresa where the locomotive going down would generate much of the suppy for a locomotive going up. The Swiss railway uses the system; three modern locomotives heading downwards generate enough power to power a single locomotive in its upward journey.
Today all eclctric locomotives tend to have drive motors close to the axles, although some still have the motor in the body driving the wheels through internal drive shafts.
Modern solid state electrical control systems means the motor does not need to match the supply. This meams multi-voltage cross border locomotives are now quite common. Drive motors are generally DC, but there are 3 phase motors on some locomotives.
A small number of electric locomotives can also operate off batery power to enable short journeys or shuting to occur on non-electrified lines or yards. Pure battery locomotives also found usage in mines and other underground workings where diesel fumes or smoke are not safe aand where external electricity supplies could not be used. Battery locomotives are also used on many underground railways for maintenance operations as they are required to operate in areas where the electricity supply has been temmporarily disconnected..
Parts of Electric Locomotive
Awynchronoux Motor
Modern traction motor type using three phase AC electrical supply and now the favoured deisgn for modern train traction systems . Can be used on DC and AC electrified. railways with suitable control electronics and on diesel-electric locomtives.
Axle Brush
The means by which the power supply ciruit is completed with the substation once power has been drawn on the locomotive. Current collected from the overhead line or third rail is returned via the axle brush and one of the running rails.
Battery
All trains are provided with a battery to provide start up current for supplying essential circuitts, such as emergency lighting ,when the line supply fails. The battery is usually connected across the DC control supply circuit.
Circuit Breaker
An electric train is almost always provied with some sort of circuit breaker to isolate the power supply when there is a fault, or for maintenance. On AC systems they are usually on the roof near the pantograph. There are two types-the air blast circuit breaker and the vacuum circuit breaker or VCB. The air or vacuum part is used to extinguish the arc which occurs as the two tips of the circuit breaker are opened. The VCB is popular in the UK and the air blast circuit breaker is more often seen on the continent of Europe.
Converter
Generic term for any solid state electronic system for converting alternating current to direct current or vice versa. Where an AC supply has to be converted to DC it is called a rectifier and where DC is converted to AC it is called an inverter. The word originated in the US but is now common elsewhere.
Cooling Fans
To keep the thyristors and other electronic power systems cool, the interior of a modern locomotive is equipped with an air management system, electronically controlled to keep all systems operating at the correct temperature. The fans are powered by an auxiliary inverter producing 3-phase AC at about 400 volts.
DC link
Used on modern electronic power systems between the single phase rectifier and the 3-phase inverter. It is easier to convert the single phase AC from the overheak line to the 3-phase required for the motors by rectifying it to DC and then inverting the DC to 3-phase AC.
Inverter
Electronic power device mounted on trains to provide alternating current from direct current. Popular nowadays for DC railways to allow three phase drive or for auxiliary supplies which need an AC supply.
Line Breaker
Electro-mechanical switch in a traction motor power circuit used to active or disable the circuit the circuit. It is nomally closed to start the train and remains closed all the time power is required. It is opened by a command from the driving controller,no-volts detected, overload detected and (were required) wheel spin or slide detected. It is linked to the overload and no-volt control circuits so that it actually functions as a protective circuit breaker.
Master Controller
Driver’s power control device located in the cab. The driver moves the handle of the master controller to apply or reduce power to the locomotive or train.
Motor Blowers
Traction motors on electric locomotives get very hot and to keep their temperature at a reasonable level for long periods of hard word, they are usually fitted with electric fans called motor blowers. On a modern locomotive,they are powered by an auxiliary 3-phase AC supply of around 400 volts supplied by an auxiliary inverter.
Rectifer
A converter consisting of thyristors and diodes which is used to convert AC to DC. A modern locomotive will usually have at least two, one for the power circuits and one or more for the auxiliary circuits.
Synchronous Motor
Traction motor where the field coils are mounted on the drive shaft and the armature coils in the housing, the inverse of normal practice.Favoured by the French and used on the high speed TGV Atlantique trains, this is a single-phase machine controlled by simple inverter. Now superseded by the asynchronous motor.
Transformer
A set of windings with a magnetic core used to step down or step up a voltage from one level to another.The voltage differences are determined by the proportion of windings in the input side compared with the proportion on the output side. An essential requirement for locomotives and trains using AC power, where the line voltage has to be stepped down before use on the train.
Equipment Layout
Ventilation System
Equipment layout and ventilation systems 設(shè)備布置和通風(fēng)系統(tǒng)設(shè)計(jì)
Equipment layout and design of the ventilation system
電力機(jī)車簡(jiǎn)介
機(jī)車是為列車提供驅(qū)動(dòng)力,而自身并沒(méi)有效裝載能力的車輛;他的唯一目標(biāo)是沿著軌道牽引列車。通常自帶動(dòng)力的車輛不被視為機(jī)車,在客運(yùn)方面自帶動(dòng)力的車輛用得越來(lái)越普遍,但是很少用在貨運(yùn)。自帶驅(qū)動(dòng)力的車輛以驅(qū)動(dòng)列車的車輛,通常它們不視為機(jī)車,因?yàn)樗鼈兙哂杏行аb載能力,并且很少?gòu)牧熊嚿险獟?,它們稱之為動(dòng)車。
一般來(lái)說(shuō),機(jī)車牽引列車。現(xiàn)今在客運(yùn)業(yè)務(wù)上拖拉式運(yùn)營(yíng)方式越來(lái)越常見(jiàn),采用這種運(yùn)營(yíng)方式的特點(diǎn)是:機(jī)車在一端牽引列車,然而卻由在另一端的司機(jī)室控制。
機(jī)車的優(yōu)點(diǎn):
在一般情況下,為什么將為列車提供驅(qū)動(dòng)力的機(jī)車和車輛是分開(kāi)的,而不是車輛自帶動(dòng)力的原因包括以下幾點(diǎn):
1. 易于維修—維修一臺(tái)機(jī)車和維修自帶動(dòng)力的車輛相比要容易。
2. 安全—通常將列車牽引動(dòng)力裝置安裝在遠(yuǎn)離乘客的地方比較安全,這一點(diǎn)對(duì)于蒸汽機(jī)車來(lái)說(shuō)顯得相當(dāng)重要,但是有時(shí)會(huì)仍然會(huì)出現(xiàn)一些不如意的情況。
3. 易于更換動(dòng)力—如果動(dòng)力裝置損壞,用一個(gè)新的來(lái)更換它即可,這樣地來(lái)顯得比較容易,從而一個(gè)動(dòng)力裝置產(chǎn)生故障時(shí)不至于整臺(tái)機(jī)車無(wú)法工作。
4. 效率—當(dāng)列車空載運(yùn)行時(shí)可以將機(jī)車從列車上摘卸下來(lái)。機(jī)車再去執(zhí)行其它牽引業(yè)務(wù),這意味著不但可以降低列車運(yùn)營(yíng)成本,還可以提高機(jī)車的使用效率。
5.將機(jī)車和車輛分離開(kāi)來(lái)意味著當(dāng)機(jī)車出現(xiàn)故障時(shí),只需更換機(jī)車就可以這樣就可以不影響列車的運(yùn)營(yíng)。在有些情況下車輛比機(jī)車先報(bào)廢,如果機(jī)車和車輛不可摘掛,那么即使機(jī)車完好也得跟著報(bào)廢,這樣就意味著浪費(fèi)和成本高,然而機(jī)車可以從列車上摘下來(lái),只需更換車輛即可,這樣五來(lái)大大的降低了成本提高了經(jīng)濟(jì)效益。
電力機(jī)車
電力機(jī)車是通過(guò)接觸網(wǎng)或第三軌由外部提供電能。盡管電氣化鐵道的造價(jià)相當(dāng)高,然而運(yùn)營(yíng)成本卻比內(nèi)燃機(jī)車低,良好的加速性能和可再生制動(dòng),使得它們?cè)诜泵Ω删€地區(qū)成為客運(yùn)業(yè)務(wù)的理想選擇。幾乎所有的高速鐵路都采用電力牽引(例如ICE,TGV),由于具有如此高的性能,機(jī)車所需要的電能是不容易得到提供。例如應(yīng)用在海底隧道貨運(yùn)業(yè)務(wù)的現(xiàn)今最大功率的機(jī)車的功率高達(dá)7MW。
第一臺(tái)電力機(jī)車由Scotsman和Robert Davidson于1837年設(shè)計(jì)并生產(chǎn),該電力機(jī)車由電流單元提供動(dòng)力。
現(xiàn)代電力機(jī)車包括從由蓄電池提供能量的用于礦山的機(jī)車到功率高達(dá)6000馬力(4.5M)甚至功率更高的干線電力機(jī)車。
事實(shí)上,現(xiàn)代許多機(jī)車它們是電力驅(qū)動(dòng)的,純電力機(jī)車是從外部獲得電能,然而內(nèi)燃電力機(jī)車它們卻自帶發(fā)電裝置。
干線電力機(jī)車第一次出現(xiàn)在20世紀(jì)初,電力機(jī)車的誕生是由于蒸汽機(jī)車產(chǎn)生在運(yùn)行過(guò)程產(chǎn)生的煙霧給駕乘帶來(lái)不便和不安全,特別是在隧道。在英國(guó)引入電力機(jī)車的是由于地鐵系統(tǒng)的需要。然而在美國(guó)引入電力機(jī)車卻是由于河底隧道這樣一個(gè)特殊的工作環(huán)境下采用內(nèi)燃牽引無(wú)法滿足要求。
早期電力機(jī)車全都依靠外部提供電能,盡管它們運(yùn)行可靠和效率高,但是建造接觸網(wǎng)是一筆相當(dāng)大的投資,并且需要不斷維護(hù)?;诖?,電氣化鐵道僅僅在繁忙干線采用。在市郊采用電氣化鐵道可以減輕由蒸汽機(jī)車燃燒所帶來(lái)的粉塵污染。
世界列車最高運(yùn)行速度紀(jì)錄由法國(guó)TGV在1990年創(chuàng)立。速度高達(dá)515.3千米每小時(shí)(320mph)。
然而,近來(lái)所設(shè)計(jì)的電氣化鐵道幾乎都采用交流制,當(dāng)然許多已有的直流供電制仍然在用,例如:南非,西班牙,英國(guó)(750V和1500V),挪威(1500V),安哥拉,意大利,波蘭(3000V),芝加哥和Mumbai(它們將由2025轉(zhuǎn)換成交流供電制)。
早期的機(jī)車有各種型式。通常它們?cè)O(shè)計(jì)成與供電制相匹配的機(jī)車。于是采用直流供電制的電氣化鐵道的鐵路系統(tǒng),電力機(jī)車的牽引電機(jī)為直流電機(jī)。采用交流供電制的電氣化鐵道的鐵路系統(tǒng),電力機(jī)車的牽引電機(jī)為交流電機(jī)。交流可以是單相,也可以是三相,單相需要兩根導(dǎo)線,一根是接觸網(wǎng),另一根是鋼軌。三相需要三根導(dǎo)線,因此三相電力機(jī)車有兩根接觸網(wǎng),鋼軌作為第三根。
直流供電可以用接觸網(wǎng)或鋼軌供電,通常稱之為第三軌。
交流牽引電機(jī)體積比直流牽引電機(jī)的體積小。通常這就意味著直流電機(jī)可以做得體積小些。安裝驅(qū)動(dòng)軸,通常采用齒輪傳動(dòng)。但是在早期也有采用軸的。即便如此,一些著名的直流電力機(jī)車采用直流電動(dòng)機(jī)驅(qū)動(dòng)車輪。
采用電力機(jī)車作為牽引動(dòng)力的一種可能就是在制動(dòng)期間電動(dòng)機(jī)可作為發(fā)電機(jī)并把發(fā)出的電能反饋給接觸網(wǎng),這種被稱之為再生抽動(dòng)。這是一個(gè)新的想法,這就是三相交流供電制為什么要采用的原因。特別是在山區(qū),機(jī)車下坡時(shí)產(chǎn)生的能量以供機(jī)車使用。瑞士鐵路采用這種系統(tǒng)。三個(gè)下程供給一個(gè)上程。
現(xiàn)今,所有電力機(jī)車都趨于將驅(qū)動(dòng)電機(jī)安裝在靠近車輪軸的位置,盡管仍有些電力機(jī)車將驅(qū)動(dòng)電機(jī)安裝在車體內(nèi)通過(guò)傳動(dòng)裝置來(lái)驅(qū)動(dòng)車輪。
現(xiàn)代實(shí)體狀態(tài)電控系統(tǒng)的采用意味著電機(jī)并不需要和供電制相匹配。因而在今天,多電壓等級(jí)的機(jī)車已相當(dāng)普遍。通常驅(qū)動(dòng)電機(jī)是直流電機(jī),但是在一些機(jī)車上也有三相驅(qū)動(dòng)電機(jī)。
蓄電池機(jī)車在礦場(chǎng)和由內(nèi)燃機(jī)產(chǎn)生的煙是一個(gè)不安全隱患的其它地下作業(yè)和外部電能不可獲得的情況下利用。蓄電池機(jī)車在許多地鐵系統(tǒng)當(dāng)供電被暫時(shí)切斷而需要維修作為維修作業(yè)車。
電力機(jī)車的各組成部分:
異步電動(dòng)機(jī)
現(xiàn)代牽引電機(jī)主要采用三相牽引電機(jī),并被廣泛應(yīng)用于現(xiàn)代列車牽引系統(tǒng).采用適當(dāng)?shù)目刂齐娮友b置后,三相牽引電機(jī)可以用在直流或交流制的電氣化鐵道和內(nèi)燃機(jī)車.
電池
所有的列車都備有電池以提供起動(dòng)電流和為一些裝置提供電源,例如當(dāng)接觸網(wǎng)供電失敗時(shí)的緊急照明,通過(guò)電池是和直流控制供電裝置相連.
斷路器
電力機(jī)車通常備有一定型式的空氣斷路器以將從接觸網(wǎng)隔離,當(dāng)機(jī)車發(fā)生故障,或者需要維修時(shí)。在交流制供電式中,斷路器通常安裝在機(jī)車頂部靠近受電弓的一側(cè)?,F(xiàn)有兩種類型的斷路器:空氣斷路器和真空斷路器(VCB)??諝饣蛘婵帐怯脕?lái)滅當(dāng)斷路器的兩連接端分開(kāi)時(shí)產(chǎn)生的電弧。真空斷路在英國(guó)用得比較多,而空氣斷路器在歐洲大陸用得比較廣泛。
逆變器
將交流轉(zhuǎn)變成直流稱之為整流,將直流轉(zhuǎn)變成交流稱之為逆變。逆變這一詞起源于美國(guó),但是現(xiàn)在這一學(xué)術(shù)用語(yǔ)在其它地方也被用。
冷卻風(fēng)扇
為了冷卻整流裝置和其它電子裝置,現(xiàn)代機(jī)車都裝有空氣管理系統(tǒng),電子控制裝置使所有的系統(tǒng)都運(yùn)行在允許的溫度范圍內(nèi)。風(fēng)扇由一臺(tái)產(chǎn)生400伏電源的三相交流的輔助逆變裝置供電。
直流連接器
在三相和單相整流器中,直流連接器用在現(xiàn)代電子電源系統(tǒng)中。通過(guò)將交流電整流成直流,然后將直流逆變成三相交流,很容易將從接觸網(wǎng)獲得的單相交流電轉(zhuǎn)變成所需要的三相交流電。
線路斷路器
在列車上安裝電力電子器件可將直流電轉(zhuǎn)換為交流電。當(dāng)今采用直流供電制的鐵路系統(tǒng)也廣泛采用三相牽引電機(jī)和一些輔助設(shè)備也采用三相交流電。
電子機(jī)械開(kāi)關(guān)
安裝在牽引電機(jī)上電子機(jī)械式開(kāi)關(guān)以斷開(kāi)和接通牽引電機(jī)電路,通常情況下開(kāi)關(guān)是閉合的。它受牽引控制器的指令控制,而并非電壓檢測(cè)傳感器的控制。它和過(guò)載檢測(cè)裝置和非電壓控制電路相連接以便在發(fā)生過(guò)載時(shí)切斷電機(jī)電路以保護(hù)牽引電機(jī)。
司機(jī)控制器
驅(qū)動(dòng)力控制裝置安裝在司機(jī)室。司機(jī)移動(dòng)司機(jī)操縱手柄以提高或減小機(jī)車牽引力。
牽引電機(jī)冷卻風(fēng)機(jī)
電力機(jī)車上的牽引電機(jī)很容易發(fā)熱,牽引電機(jī)在長(zhǎng)時(shí)間滿負(fù)荷運(yùn)行式?jīng)r下,為了使其溫升在允許的范圍內(nèi),通常給牽引電機(jī)安裝有風(fēng)扇稱之為冷卻風(fēng)機(jī)。在現(xiàn)代機(jī)車上,風(fēng)扇由一臺(tái)產(chǎn)生400伏左右電源的三相交流輔助逆變裝置供電。
整流器
整流器由將交流轉(zhuǎn)換為直流的可控硅和二極管組成。通?,F(xiàn)代電力機(jī)車至少有兩個(gè)整流器,一個(gè)用于主電路的整流,一個(gè)用于輔助電路的整流。
同步電動(dòng)機(jī)
牽引同步電機(jī)是 勵(lì)磁線圈安裝在驅(qū)動(dòng)軸上 電樞線圈安裝在定子上的電機(jī), 這和通常的電機(jī)剛好相反。這種電機(jī)在廣泛應(yīng)用在法國(guó)用于高速列車用得由法國(guó)和它采用了高速的TGV大西洋列車 這是一種由簡(jiǎn)單逆變器控制的單相電機(jī)?,F(xiàn)在已被異步電動(dòng)機(jī)取代了 。
變壓器
變壓器是由鐵芯和繞組組成且將電壓由一個(gè)等級(jí)升高或降低到另一個(gè)等級(jí)的設(shè)備。變壓器的輸出電壓由輸入側(cè)和輸出側(cè)繞組匝數(shù)之比決定。變壓器作為電力機(jī)車不可缺少的設(shè)備其將從接觸網(wǎng)的電壓變換成機(jī)車在牽引工況下所需電壓。
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