538 中央傳動及轉(zhuǎn)向離合器設(shè)計（有cad圖+中英文翻譯）,538,中央傳動及轉(zhuǎn)向離合器設(shè)計（有cad圖+中英文翻譯）,中央,傳動,轉(zhuǎn)向離合器,設(shè)計,cad,中英文,翻譯 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 Equipment layout and design of the ventilation system