【正文】 reed pipes and so on to constitute the frequency conversion water supply intelligent control system. And to save the cost ,It uses relay and contractor to finish the logical control, the frequency changer to finish the pressure control, the pressure transmitter time track water pump outlet pressure and assigns the value of pressure the deviation change, sends in the frequency changer after the PID regulator internal arithmetic, controls 3 electrical machinery by the control circuit to stop as well as the power frequency and the frequency conversion cut, realizes the closed loop automatic control constant pressure frequency conversion water supply, maintains the constant pressure the premise issues the control current capacity the system , automatic control, stable property merit.KEY WORDS: Relay, Contacor, Vaviable frequency Control, Constant pressure water 3supply目錄前言 ............................................................................3 供水技術(shù)應(yīng)用.............................................................3 變頻恒壓供水系統(tǒng)的發(fā)展...................................................4 本課題所需工作...........................................................5第一章 系統(tǒng)組成及可行性分析 .....................................................6 變頻調(diào)速的基本原理 ......................................................6 變頻恒壓調(diào)速在供水系統(tǒng)中的應(yīng)用...........................................6 系統(tǒng)工藝流程.............................................................6 控制要求及技術(shù)指標(biāo).......................................................74 可行性分析，節(jié)電分析 ....................................................8第二章 系統(tǒng)設(shè)計 .................................................................9 主電路設(shè)計...............................................................9 變頻器的工作原理 ...................................................9 變頻器的發(fā)展 ......................................................10 電機運行的控制 ....................................................11 工頻變頻切換與變頻器工作的時序的關(guān)系 ..............................11 PID 調(diào)節(jié)器的應(yīng)用和原理 ............................................11 確定控制方案............................................................14 手動運行 ..........................................................15 自動運行 ..........................................................15 保護和報警系統(tǒng) ....................................................16 儀表顯示 ..........................................................17 控制電路圖 ........................................................17第三章 設(shè)備選型 ................................................................20 變頻器選型 ...........................................................20 水泵電機的選擇 ..........................................................20 接觸器 ..................................................................21 繼電器 ..................................................................21,1 熱繼電器 .........................................................21 時間繼電器 .......................................................22 中間繼電器 .......................................................22 低壓斷路器 .............................................................22 壓力變送器 .............................................................23 調(diào)節(jié)器 .................................................................23 干簧管 .................................................................24 頻率顯示儀表 ...........................................................24 按鈕，萬能開關(guān) ........................................................24 指示燈 ................................................................245 警鈴 ..................................................................25 固定線槽的選用 ........................................................25 接線端子排的選用 ......................................................25第四章 控制柜設(shè)計..............................................................26 相關(guān)布置規(guī)定 ...........................................................26 設(shè)計準(zhǔn)備工作......................................................26 控制柜布局和器件配置 ...............................................26 控制柜內(nèi)部布置 .........................................................27 面板布置 ...............................................................27第五章 結(jié)論....................................................................28 系統(tǒng)總結(jié) ...............................................................28 系統(tǒng)特點 ...............................................................28結(jié)束語.........................................................................29致謝...........................................................................30參考文獻..........................