工矿机电设备相序保护器的设计与应用

Design and research of phase sequence protector for mine electro-mechanical equipment

针对有些工矿机电设备必须考虑相序、由于相序错误导致电机反转会造成严重后果、但传统相序保护器只对错相保护而对缺相状况无能为力的问题,设计一种全新保护器,该保护器对三相来电分别采样、整形,得到三个逻辑方波送到相序判别逻辑控制单元,对于正常相序,控制单元产生一系列脉冲通过晶体管驱动LED发光,与LED封装在一起的光敏电阻受光照后使另一开关管得到基极偏流而导通,使接触器吸合,电机得电启动运转;反之,假如接错相序或电源缺相,指示灯会熄灭,接触器断开,电机停转保护人身财产安全。该保护器可以制作成一个电路模块,随时配合任何一台三相交流机电设备完成保护工作。经过煤矿实际应用,该保护器应用灵活、性能稳定,性价比较高。

The phase sequence of some mine electro- mechanical equipment must be considered,as motor reversal caused by wrong phase sequence will cause serious consequences,while traditional phase protector is incapable for phase loss,a new phase sequence protector is designed,which separately samples and reshapes the three- phase incoming power,and transmitted the three logic square wave to discrimination logic control unit of phase sequence. For normal phase sequence,control unit generates a series of pulses driving LED light through a transistor,and the photoresistance encapsulated with LED is activated by light,another switch tube is conducted with base bias current,activating the contactor and the electric motor; conversely,when wrong sequence or phase loss happens,the LED is off,the contactor disconnects,and the motor stops. The protector can be made into a circuit module,to match up with any three- phase AC electromechanical equipment at any time. The practical application in coal mine shows that, the protector is flexible and stable in application,has favorable cost performance.