基于PLC的电动机的综合保护(毕业设计）改1.doc

基于PLC的异步电动机的综合保护 摘要 本文主要研究了基于PLC的电动机综合保护系统，介绍了可编程序控制器的功能特点和发展现状，叙述了电动机的过载、断相、短路、过/欠压等故障类型的特点及其保护原理；阐述了保护系统硬件的构成；并编写了PLC保护程序，给出了I/O分配图和梯形图。 根据不同的故障类型采用不同的动作原理，分别设计其保护时限；采样电路把模拟量传入PLC的CPU，由CPU根据事先定好的整定值做出判断，来决定是否启动相应的保护子程序，当检测量超过整定值时，PLC将启动相应的继电器和寄存器，并显示故障类型；根据设计程序动作断开电动机的电源，从而实现电动机的保护。保护使用台达机型为主体，A/D转换模块用台达自带的4路转换模块，应用TD220来显示数据和故障类型。 关键词： 可编程序控制器 三相异步电动机 梯形图 The Synthesis Protection Based on PLC of Three-phase Asynchronous Motors Abstract This article has mainly studied based on the PLC electric motor synthesis protection system, introduced the programmable controller function characteristic and the development present situation, narrated the electric motor overload, broke, the short circuit, the over voltage and owes the voltage and so on the breakdown type characteristics and the protection principle; Elaborated the protection system hardware constitution; And has compiled the PLC protection procedure, has given I/O distribution diagram and trapezoidal chart. Uses the different movement principle according to the different breakdown type, designs its protection time limit separately. The sampling electric circuit spreads to the simulation quantity PLC CPU, arranges the installation value by the CPU basis to make the judgment beforehand, decided whether starts the corresponding protection subroutine, when the examination quantity surpasses the installation value, PLC will start the corresponding relay and the register, and will demonstrate the breakdown type. Separates the electric motor according to the design procedure movement the power source, thus realizes the electric motor protection. The protection uses Taiwan to reach the type is the main body, A/D transformation module reaches bringing with Taiwan 4 group transformation module, using TD220 to demonstrate the data and the breakdown type. Keywords: Programmable Logical Controller, three-phase asynchronous motor, trapezoidal chart 目录 摘要 I Abstract II 1 绪论 1 1.1 引言 1 1.2 电机保护在国民经济和节能事业中的重要意义 2 1.3