关键词：恒压变频供水；PLC；变频器
Application of The Frequency Control of Motor Speed in The City’s Water Supply System（Design Proposal One of PLC and Frequency convertor）
ABSTRACT
On the basis of analyzing the development and characteristic of automatic system of water supply, combined with the waterworks in our country, this text designs a water supply system based on variable frequency speed-regulating technology.
This text has introduced the basic principle that constant voltage supplies water and foundation that the system form , have stated the role served as of the programmable controller (PLC ) in the water -supply system of constant voltage. And has introduced according to the network management pressure, controls water pump's rotational speed through the inverter, causes in water pipe's pressure maintains at throughout the appropriate scope, thus may solve the problem which the floor high pressure is too insufficient when small current capacity the energy consumption is big. This text since the whole design plan of the system and actual demand are analysed, the need of close life of intergrating with practice, make every effort to make sure to make the system run steadily, easy and simple to handle, solve and hit the problem actually, guarantee to supply water of the security, swift , reliable.In order to pump water for the people under the uncommon condition of the frequency invertor ,this systerm has designed manual-controller.
Key words： Constant pressure frequency conversion water supply； PLC；frequency convertor
