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【正文】 鐵道出版社，2007[3]周鈍熊，PLC在鐵路信號(hào)連鎖控制中心的應(yīng)用[M]．上海：上海鐵道學(xué)院，1999[4]趙志熙，車站信號(hào)控制系統(tǒng)[M]．北京：中國(guó)鐵道出版社，1993[5]趙躍華，可編程控制器及其應(yīng)用[M]．四川：電子科技大學(xué)出版社，1998[6]周治邦，鐵路信號(hào)現(xiàn)場(chǎng)總線控制的基本研究[M]．北京：鐵道學(xué)報(bào)，1999[7]中國(guó)機(jī)械自動(dòng)化研究委員會(huì)．PLC技術(shù)及應(yīng)用[M]．北京：機(jī)械工業(yè)出版社，2000[8]陳小鳳，鐵路信號(hào)現(xiàn)場(chǎng)控制技術(shù)[M]．北京：清華大學(xué)出版社，2000[9]常斗南，可編程控制器PLC工作原理[M]．北京：機(jī)械工業(yè)出版社，2001[10]朱善君，可編程器PLC仿真概述[M]．北京：清華大學(xué)出版社，1995[11]黃靜，PLC梯形圖編程技巧[M]．上海：上海鐵道學(xué)院出版社，1994[12]沈潔，PLC實(shí)際應(yīng)用概述[M]．北方交通大學(xué)出版社，1998[13]魏文君，計(jì)算機(jī)連鎖在鐵路運(yùn)輸中的應(yīng)用技術(shù)甘肅[N]．甘肅鐵道學(xué)報(bào)，1997[14]Online changes of train control system without train stopping [A].the academic journal of Cambridge of .[15]Railroad identity design and culture [A].New .[16]Railway Track and structures[C].[17]Development ofRailwaySignal Control[j].[18]Based onthe advantages ofPLCin railwayapplications[j].附 錄一、英文原文A AC MachinesIntroductionThe electrical machine that converts electrical energy into mechanical energy, and vice versa, is the workhouse in a drive system A machine is a plex structure electrically, mechanically, and thermally. Although machines were introduced more than one hundred years ago, the research and development is this area appears to be neverending. However, the evolution of machines has been slow pared to that of power semiconductors devices and power electronic converters. Traditionally AC machines with a constant frequency sinusoidal power supply have been used in constantspeed applications whereas DC machines were preferred for variablespeed drives. But in the last two or three decades, we have seen extensive research and development efforts for variablefrequency ,variablespeed AC machine drive technology, and they will progressively replace DC drives. In most cases, new applications use AC drives.AC machines can generally be classifies as follows:Induction machines: Cage or wound rotor (doublyfed), Rotating or linear。Synchronous machines: Rotating or linear, Reluctance, Wound field or permanent magnet, Radial or axial gap (disk), Surface magnet or interior(buried) magnet ,sinusoidal or trapezoidal。Variable reluctance machines: Switched reluctance, stepper.Induction MachinesAmong all types or AC machines, the induction machine, particularly the cage type, is most monly used in industry. These machines are very economical, rugged, and reliable and are available in the ranges of fractional horse power (FHP) to multimegawatt capacity. Lowpower FHP machines are available in singlephase, but polyphase (threephase) machines are used, most often in variablespeed drives. Fig. 16A1 shows an idealized threephase, twopole induction motor where each phase windings in the stator and rotor is represented by a concentrated coil. The threephase windings are distributed sinusoidally and embedded is slots. In a cage machine, the rotor has a squirrel cagelike structure with shorted end rings. Basically, the machines can be looked upon as a threephase transformer with a rotating and shortcircuited secondary. Both stator and rotor cores are made with laminated ferromagnetic steel sheets. The air gap in the machine is practically uniform (nonsalient pole).One of the most fundamental principles of induction machines is the creation of a rotating and sinusoidally distributed magnetic field is the air gap. Neglecting the effect of slots and space harmonics due to nonideal winding distribution, it can be shown that a sinusoidal threephase balanced power supply in the threephase stator winding crates a synchronously rotating magnetic field. The rotational speed can be given as equation (16A1). Ne is called synchronous speed in rpm and Fe=ωe/2π is the stator frequency is Hz . P is the pole numbers of a machine.Ne=120Fe/PThe rotor winding will be subjected to a sweeping magnetic filed, and have inducing current in the shortcircuited rotor. The interaction of air gap flux and rotor mmf produces torque, make the rotor rotate. But the speed of the rotor is lees than synchronous speed. So it called induction machine or asynchronous machine. To meet the various staring and running requirements of a variety of industrial applications, several standard designs of squirrelcage motors are available from manufacturers stock. The torquespeed characteristics of the most mon designs, readily available and standardized in accordance with the criteria established by the National Electrical Manufacturers Association , are shown in Fig 16A2. The most significant design variable in these motors is the effective resistance of the rotor cage circuits.Class A Motors These machines are suitable for applications where the load torque is low at start(such as fan or pump loads)so that full speed is achieved rapidly, thereby eliminating the problem of overheating during starting. In large machines, lowvoltage starting is required to limit the starting current.Class B Motors Motors of this class are good generalpurpose motors and have a wide variety of industrial applications. They are particularly suitable for constantspeed drives, where the demand for starting torque is not severe. Examples are drives for fans, pumps, blowers, and motorgenerator sets.Class C Motors Class C motors are suitable for driving pressors, conveyors, and so forth.Class D Motors These motors are suitable for drives intermittent loads requiring rapid acceleration and highimpact loads such as punch presses or shears. In the case of impact loads, a flywheel is fitted to the system. As the motor speed falls appreciably with load impact, the flywheel delivers some of its kinetic energy during the impact.Synchronous MachinesA synchronous machine, as the name indicates, must rotate at synchronous speed, that is, the speed is uniquely related to the supply frequency, as indicated in Equation (16A1). It is a serious petitor to the induction machine invariablespeed drive applications. an idealized threephase, twopole wound field synchronous machine. The stator winding o