摘要
电动机在运行中经常会由于使用不当而引发各种故障,造成电动机损坏,影响经济生产。多功能电动机综合保护器能够根据负载电流判断线路中的各种故障并及时进行保护,最大限度的减少经济损失。本文在分析了目前国内外电动机保护器的研究进展与现状的基础上,设计了一种以PIC16F877单片机为控制核心,集短路、堵转、断相、过载、过压和欠压等故障保护于一体的多功能电机综合保护器。
本文首先对电动机的相间短路、堵转、断相、过载、过压和欠压等常见电气故障进行了详细分析,并结合PIC16F877单片机的功能特点,提出了可靠性高、实施性强的故障保护实现方法。控制核心采用PIC16F877单片机,其AD转换接口用于输入电机电压、电流采样,结构紧凑,与现有电机综合保护仪相比,增加了动态液晶显示驱动电路用于显示各种信息等功能。
根据文中提出的各类故障保护实现方法,设计并实现了电动机保护装置完整的硬件电路,给出了保护装置完整的系统软件实现方案。
关键词 :三相电机保护器; 单片机; 保护特性
Abstract
The production process are broken frequently due to the motor in operation are damaged, which is caused by abnormally running conditions. The intelligent motor protectors can be used, which will protect the abnormally running motors from damage, to minimize the malfunction time and reduce the economic losses. In this paper, a single-chip microcomputer, PIC16F877, based intelligent motor protector with functions of short-circuit protection,locked motor protection,phrase failure protection ,the overload protection ,over-voltage protection and under-voltage protection is designed on the basis of analyzing the development and status quo of motor protectors in the world.
In this thesis, the detailed analysis applied symmetrical component method of motor’s familiar electric fault on that a high-reliability implemental method of motor’s fault protection is provided according to the features of PIC16F877 microprocessor. The system is provided with A/D conversion interface used to sampling the input current of the motor and the structure is compact. Compared with the protection instrument for motor nowadays, this system increases functions such as dynamic LCD screen driven circuit to display different information.
According to the implemental method of motor’s fault protection the entire circuit diagrams are designed and the system software structure been easy to implement.
Keywords:Three-phrase motor protection; Single chip microcomputer; protection characteristic