有关异步电动机的中英翻译资料.doc

异步电动机起动方法和问题都有潜在优势功率因数校正电容器可以用来减电流本文将探讨最常见的电机启动 降压启动 自耦功率因数校正部分绕组类型 由于用此方法启动电机会使启动电流达到电机额定电流的六到七倍，因此方法也是给供电系统带来最大的压力的方法。如果供电系统比较薄弱，大功率电机的突然启动不仅会使电动机的电压瞬间下降，而且会使给电机供电的整个母线端电压下降。电压下降会使此电动机的启动转矩和工作在同一母线上的电动机的转矩下降。异步电动机的转矩大约和输入电压的平方成比例变化。因此，由于电压的大幅下降，工作在此供电系统的电动机可能停车。另外许多控制系统监控器工作在低电压下，第二个全压启动时电压问题会使正在运行的电机离线。同时，母线电压变化，直接启动的另一个问题驱动设备突然被加载。由于瞬时转矩可以超过转子制动转矩的600%，这个冲击负荷会增加设备的磨损，如果负载不能承受由电机启动产生的力矩，甚至会造成灾难性故障。 A．电容器和启动 异步电动机功率因数通常很低,因此在开始有很大的避免过电压和损坏 应小心确保电容器电机达到额定转速,否则由于功率电容器提供磁化电流不会进入模式. 这将在一段和附录电容器也可永久留下提高满载功率因数当使用这种方式被称为功率因数校正电容器但是在一些应用场合这还是有问题的。自耦起动另一个好处是尽可能降低振动和噪音应非常谨慎,以确保电动机足够的加速转矩一个好的经验法则是至少有10%的额定矩作为曲线各点这些装置采用最常用软起动器的限流型到500%，启动电流和启动力矩下降2/3。根据应用，电机切换到三角形可在转速为50% 到最大速度之间。必须指出,同样的问题,包括先前谈到的切换这些方法也可能导致不得不加大电机尺寸以产生转矩所需的负荷整个速度范围内产生满载转矩最高可达10:1允许一个很大程度的控制电阻器或起动INDUCTION MOTOR STARTING METHODS AND ISSUES Abstract - Many methods can be used to start large AC induction motors. Choices such as full voltage, reduced voltage either by autotransformer or Wyes - Delta, a soft starter, or usage of an adjustable speed drive can all have potential advantages and trade offs. Reduced voltage starting can lower the starting torque and help prevent damage to the load. Additionally, power factor correction capacitors can be used to reduce the current, but care must be taken to size them properly. Usage of the wrong capacitors can lead to significant damage. Choosing the proper starting method for a motor will include an analysis of the power system as well as the starting load to ensure that the motor is designed to deliver the needed performance while minimizing its cost. This paper will examine the most common starting methods and their recommended applications. Index Terms: motor starting. Reduced voltage start auto transformer, wyes-delta, power factor correction I. INTRODUCTION There are several general methods of starting induction motors: full voltage, reduced voltage, wyes-delta, and part winding types. The reduced voltage type can include solid state starters, adjustable frequen