PLC恒压变频供水控制系统设计.doc

摘 要 建设节约型社会，合理开发、节约利用和有效保护水资源是一项艰巨任务。根据生活小区用水时间集中，用水量变化较大的特点，分析了小区原供水系统存在成本高，可靠性低，水资源浪费，管网系统待完善的问题。提出以利用自来水水压供水与水泵提水相结合的方式，并配以变频器、PLC、压力传感器、液位传感器等不同功能的传感器，根据管网的压力，通过变频器控制水泵的转速，使水管中的压力始终保持在合适的范围。从而可以解决因楼层太高导致压力不足及小流量时能耗大的问题。 另外水泵耗电功率与电机转速的三次方成正比关系，所以水泵调速运行的节能效果非常明显，平均耗电量较通常供水方式节省近四成。结合使用可编程控制器，可实现主泵变频，具有短路保护、过流保护功能，工作稳定可靠，较大的延长了电机的使用寿命。 关键词：恒压变频供水 变频器 PLC 自动控制 ABSTRACT Building the conservation-oriented society, the reasonable development, saves and the effective protecting water resources is an arduous task. According to the characteristic of the time to focus on water of the domestic and variation in water consumption ,it analyzes that there are questions that highly cost ,low reliability ,the water-resources waste, and the consummate of ?the pipe network system of the old water-supply system in the residential area. So we proposed that we could make use of the way of?combining hydraulic pressure water supply of the running water with?the water pump, and accompanied by the transducer, PLC, the pressure sensor, the fluid position sensor and so on. According to the pressure of the network management, it could maintain the pressure of the pipe in appropriate range through controlling rotational speed of the water pump through the inverter commands .Thus we may solve the problem that the insufficient pressure caused by the high floor and the high energy consumption when the current is small. Moreover? the electric power consumption of the water pump and the rotational speed of the electrical machinery? is proportional three cubed the relations, therefore the energy conservation effect of ?the water pump velocity modulation movement is obvious, the average power consumption usual water supply way saves 40%.Combined with the programmable controller, we may realize the main pump frequency conversion which has the short circuit protection, the overflow protection function stably and the work reliable, thus we extend electrical machinerys service life greatly. Key w