三相交流同步发电机的组成及工作原理介绍.doc

三相交流同步发电机的组成及工作原理介绍三相同步发电机由原动机拖动直流励磁的同步发电机转子，以转速n(rpm)旋转，根据电磁应原理，三相定子绕阻便感应交流电势。定子绕阻若接入用电负载，电机就有交流电能输出。若认为磁路不饱和，则电枢磁势与磁极磁势各自产生相应的磁通，并在定子绕阻 内感因电势。对于 极电机，电枢磁势所感应的电势可以表示为Ea=-jIaXa. Xa被称为电枢反应电抗。 Xa+X=Xs隐极同步发电机的同步电抗。对于凸极电机，因直轴.交轴处磁阻不同，可将电枢磁势分解成Fad和Faq分别研究。它们所感应的电势分别写成Ead=-jIdXad和Eaq=-jIqXaq，式中Xad.Xaq分别是直轴及交轴电枢反应电抗。Xad+X=Xd.Xaq+X=Xq,Xd和Xq分别为直轴同步电抗和交交轴同步电抗。X为漏磁通引起的电抗 。同步电抗是决定同步电机性能的一个重要参数，通个开路实验和稳态实验就可求取。 同步发电机的空载特性是一个很重要的特性，它直接影响着电机的其它特性，通个开路实验还可以发现励磁系统的故障。态短路特性和零功率因数特性也都属于同步电机的重要特性，和空载特性配合，可以求出同步发电机的态参数及确定出补偿电枢的励磁电流。 同步发电机的外特性曲线用来求取电机运行时的重要指标之一及电压调整率。 同步发电机的调整特性可使运行人员知道在功率因数一定时，不改变端电压值.负载电流到多小而不使励磁电流超过规定值。 国家标准GB1029 对三相同步电机的实验方法作了具体规定，适用于普通三相同步发电机的型式实验或检查实验。通过实验可以确定该电机各性 能指标。各种电机的效率和电压调整率均在部颁标准的相应技术条件中有具体规定，将实验结果与标准规定数据比较即可确定某同步发电机的质量和性能了。 若求取额定励磁电流和电压变化率，一般用做图法，跟国家标准GB1029介绍，其具体步骤如下： （1） 如图1上绘制开路特性曲线，并沿纵轴额定相电压相量UN. （2）自原点O作额定电枢电流相量IN，与纵轴成N角（cosN 为额定功率因数）。 （3）从相量UN终端作出电枢绕组电阻压降INRa平行与相量 ，IN,Ra为基准工作温度时的绕组电阻（对大型电机的Ra可忽略不计，对小型电机可进可行实际测量），从INRa终端作一垂直于相量IN的保梯电抗压降相 量INXp（Xp的保梯电抗压降相量INXp（Xp的求法见下（5），UN和INRa及 和INRa及INXp的相量和为相量Ep,Ep和UN的夹角。 （4）由开路特性确定的对应于Ep的励磁电流为Ifp在相量终端上与纵 与纵轴成+N角做相量Ifa （5）额定电枢电流时电枢反应的励磁电流Ifa和保梯电抗Xp的确定： 如右下图上的开路特性曲线，并在图上作F点，F点的纵坐标为额定电压，横坐标为零功率因数特性上对应于于额定电枢电压.额定电枢电流的励磁电流通过通过F点作平行于横轴的直线CF，取CF的长度等于三相稳态短特性曲线上对应于额定枢电流的励磁电流Ifk，自点C作直线平行于开路特性的直线部分于开路特性交于H，自CF作的垂线HK交CF于K，线段 HK的长度即为额定电枢电流时在保梯电流电抗Xp上的压降Up，则保梯 电抗Xp，可按下式计算。 XpUpIN 若用标么值绘制开路特性曲线时,则,即可直接得出.线段的长度代表对应于时的励磁电流. ?(6)与的向量和即为额定励磁电流。 （7）由开路特性曲线求出对应与开路电压。电压变化率按下式机算 U=（U0-UN)/UN*100 注：实验室里为教学实验用的同步电机通常是小型的。 发电机概述 发电机是将其他形式的能源转换成电能的机械设备，它由水轮机、汽轮机、柴油机或其他动力机械驱动，将水流，气流，燃料燃烧或原子核裂变产生的能量转化为机械能传给发电机，再由发电机转换为电能。发电机在工农业生产，国防，科技及日常生活中有广泛的用途。 发电机的形式很多，但其工作原理都基于电磁感应定律和电磁力定律。因此，其构造的一般原则是：用适当的导磁和导电材料构成互相进行电磁感应的磁路和电路，以产生电磁功率，达到能量转换的目的。 发电机已实施出口产品质量许可制度，未取得出口质量许可证的产品不准出口。 发电机的分类可归纳如下： 发电机分：直流发电机和交流发电机 交流发电机分：同步发电机和异步发电机(很少采用) 交流发电机还可分为单相发电机与三相发电机。 发电机结构及工作原理 发电机通常由定子、转子、端盖及轴承等部件构成。 定子由定子铁芯、线包绕组、机座以及固定这些部分的其他结构件组成。 转子由转子铁芯(或磁极、磁扼)绕组、护环、中心环、滑环、风扇及转轴等部件组成。 由轴承及端盖将发电机的定子，转子连接组装起来，使转子能在定子中旋转，做切割磁力线的运动，从而产生感应电势，通过接线端子引出，接在回路中，便产生了电流。 柴油发电机工作原理 柴油机驱动发电机运转，将柴油的能量转化为电能。 在柴油机汽缸内，经过空气滤清器过滤后的洁净空气与喷油嘴喷射出的高压雾化柴油 充分混合，在活塞上行的挤压下，体积缩小，温度迅速升高，达到柴油的燃点。柴油被点燃，混合气体剧烈燃烧，体积迅速膨胀，推动活塞下行，称为作功。各汽缸按一定顺序依次作功，作用在活塞上的推力经过连杆变成了推动曲轴转动的力量，从而带动曲轴旋转。 将无刷同步交流发电机与柴油机曲轴同轴安装，就可以利用柴油机的旋转带动发电机的转子，利用电磁感应原理，发电机就会输出感应电动势，经闭合的负载回路就能产生电流。 这里只描述发电机组最基本的工作原理。要想得到可使用的、稳定的电力输出，还需要一系列的柴油机和发电机控制、保护器件和回路。 详细请进 汽油发电机原理 汽油机驱动发电机运转，将汽油的能量转化为电能。 在汽油机汽缸内，混合气体剧烈燃烧，体积迅速膨胀，推动活塞下行作功。各汽缸按一定顺序依次作功，作用在活塞上的推力经过连杆变成了推动曲轴转动的力量，从而带动曲轴旋转。将无刷同步交流发电机与汽油机曲轴同轴安装，就可以利用汽油机的旋转带动发电机的转子，利用电磁感应原理，发电机就会输出感应电动势，经闭合的负载回路就能产生电流。The composition of the three-phase AC synchronous generator worksThree-phase synchronous generator prime mover drag DC excitation synchronous generator rotor speed n (rpm) rotation, should be the principle of electromagnetic, three-phase stator windings, induction AC potential. The stator winding if the access to electricity load, the motor there is AC power output. If the magnetic circuit is not saturated, the armature magnetic potential and the magnetic pole magnetic potential corresponding flux, and the sense of the stator winding due to the potential. Pole motor, the electric potential induced by the armature magnetic potential can be expressed Ea = jIaXa. Xa is called the armature reaction reactance. Xa + X, = Xs, salient pole synchronous generator synchronous reactance. Salient motor, due to the direct axis cross the axis at the reluctance of different armature magnetic potential can be decomposed into a Fad and Faq were studied. Their induction potential written Ead =-jIdXad Eaq = the-jIqXaq, where Xad.Xaq are direct axis and quadrature axis armature reaction reactance. Xad + X = Xd.Xaq + X = Xq, Xd and Xq, respectively, for the direct axis synchronous reactance and cross-quadrature-axis synchronous reactance. X for magnetic flux leakage reactance. Synchronous reactance is an important decision to the synchronous motor performance parameters through the open experiment and steady-state experiments can strike.The no-load characteristics of synchronous generator is a very important feature, which directly affects the other characteristics of the motor through an open experiment can be found in the excitation system failure. The state short-circuit characteristics and zero power factor characteristics are also important characteristics of a synchronous motor, and load characteristics with the state parameters of the synchronous generator can be obtained and to determine the compensation of the armature excitation current.The external characteristic curve of the synchronous generator is used to strike an important indicator of the motor is running and voltage regulation.Synchronous generator adjustment feature allows the operating personnel know when the power factor does not change the terminal voltage value. Load current to the many small rather than the excitation current exceeds the specified value.The national standard GB1029 three-phase synchronous motor, experimental methods, specific provisions apply to the ordinary three-phase synchronous generator type of experiment or check experiments. Experiment can determine the motors performance. Motor efficiency and voltage regulation rate specified in the ministerial standards of the corresponding technical conditions, the experimental results with the standard specifies the data to determine the quality and performance of a synchronous generator.Strike a rated excitation current and voltage rate of change, generally used for the diagram method, with the national standard GB1029, the following concrete steps:(1) Figure 1 drawn on the open-circuit characteristic curve, and along the longitudinal axis of the rated phase voltage relative to the amount of the UN.(2) the origin O of the rated armature current phasor IN, and the vertical axis into N corner (cosN for rated power factor).(3) made from the phasor UN terminal armature winding resistance voltage drop INRa parallel phasor, IN, Ra operating temperature of the winding resistance (large motor Ra is negligible, small motor into feasible actual measurement electric compression), from a vertical INRa terminal phasor IN potier drop phaseAmount INXp (the Xp protection ladder electric compression drop phasor INXp (Xp evaluation method below (5) UN and INRa, andAnd INRa and INXp the phasor and phasor Ep Ep and the UN the angle .(4) determined by the open characteristics of the corresponding Ep excitation current Ifp phasor terminal and longitudinal + N angle phase the amount of Ifa and the vertical axis(5) The rated armature current armature reaction excitation current the Ifa potier reactance Xp to determine:Power factor characteristics of the lower right on the map, the open circuit characteristic curve and the vertical axis on the graph for the point F to point F for the rated voltage, the abscissa zero corresponds to the rated armature voltage excitation current of the rated armature current through F for the straight line CF parallel to the horizontal axis, take the CF of length equal to three-phase steady-state short-characteristic curve corresponds to the rated armature current of the excitation current Ifk a straight line from point C parallel to the straight part of the open circuit characteristics in the open features intersect at H, since the CF for the perpendicular HK to pay CF K, line segmentsHKs length is the rated armature current pressure drop ensure the ladders current reactance Xp Up, then the insurance ladderReactance Xp, can be calculated as follows.Xp = Up / INWith unit value of the characteristic curve drawn open, can be directly obtained the length of the representative of the line corresponds to at the time of the excitation current.? (6) with the vector and is rated excitation current.(7) by the open-circuit characteristic curve obtained corresponds to the open circuit voltage. Voltage rate of change of press-type machine operator U = (U0-UN) / UN * 100Note: The synchronous motors are usually used for teaching experiments in the laboratory is small. generator OverviewThe generators are other forms of energy into electrical energy machinery and equipment, turbines, steam turbines, diesel engines, or other dynamic mechanical drive, water, air, fuel combustion or nuclear fission energy into mechanical energy to pass the generator, and then converted to electricity by the generator. Extensive use of generators in the industrial and agricultural production, national defense, science and technology and everyday life.The form of a generator, but their works are based on the law of electromagnetic induction and electromagnetic force law. Therefore, the general principles of its structure: mutual electromagnetic induction of the magnetic circuit and circuit to generate the appropriate magnetic and conductive materials constitute the electromagnetic power, to achieve the purpose of energy conversion.The generator has been implemented for the system of export product quality permit, without obtaining the export quality license is not allowed to export. Generator classification can be summarized as follows:Generator: DC generators and alternatorsAlternator: synchronous generators and asynchronous generators (rarely used)The alternator can be divided into single-phase generator and three-phase generator. generator structure and working principleThe generator usually by the stator, rotor, end caps and bearings and other components.Stator consists of a stator core, the line winding consists of a docking station and a fixed part structure.Rotor by the rotor core (or magnetic pole, magnetic choke) windings, retaining ring, center ring, slip rings, the fan and shaft and other components.By the bearing and end cap connected to the generator stator and rotor assembly together, so that the rotor can rotate in the stator to do the cutting of the movement of the magnetic field lines, resulting in the EMF, leads to the terminals, connected to the circuit will produce a current.Diesel generator worksDiesel engine driven generator running, the diesel energy into electricity.Diesel engine cylinder, high pressure jet of clean air after the air cleaner filter and nozzle atomized diesel full hybrid, and squeezed the piston upward, the volume is reduced, the temperature rapidly increased, reaching the ignition point of diesel. Diesel fuel was ignited, severe burning of the gas mixture, the rapid expansion of volume, to promote the piston downward, known as the power. Each cylinder according to a certain order of power, into a role after the connecting rod in the piston on the thrust force driving the crankshaft, so as to drive the crankshaft rotation.The brushless synchronous AC generator with diesel engine crankshaft coaxial installat