煤礦井下排水系統控制的系統設計畢業論文-資料下載頁

　　

【正文】 要監測壓力、電流、溫度、流量等狀態量，出現異常停止水泵，并報警給出故障提示。其流程圖如圖54所示。圖54運行過程故障保護流程水位在水泵的作用下逐漸下降，直到達到需要關閉水泵的水平，即水位下降到安全水位以下，這時要先關閉排水管的電動閘閥，再關閉逆止閥，防止排水管中井水倒流，隨后關閉水泵電機，使其停止工作。如果排水閥，逆止閥，電機關閉沒有到位，則觸發聲光報警，緊急停泵，其流程如圖55。圖55 停泵流程圖停止過程中主要結合定時器監測動作是否正常，出現故障進行報警，并給出故障提示。其流程圖如圖56所示。圖56停止過程故障保護流程FC1模塊設計:程序段1：用位存儲器M100代替輸入存儲器I0。程序段2：用位存儲器MW110代替輸入存儲器PIW256。程序段3：用位存儲器M150代替輸出存儲器Q4。OB1主模塊設計:程序段1：調用指令CALL實現調用FC1模塊的功能。所以，在OB1模塊的開始就進行了地址轉移。程序段2：10泵采集的真空度、電機電流、電機溫度（PLC內部已將其轉化為0～27648）與設定值相比較。程序段3：20泵采集的真空度、電機電流、電機溫度與設定值相比較。程序段4：30泵采集的真空度、電機電流、電機溫度與設定值相比較。本章介紹了煤礦井下排水系統的軟件設計方案。分別給出系統整體的軟件流程圖、水泵的自動開啟關閉、故障保護的流程圖，以及給出部分STEP7編程程序。完成了整個系統的軟件設計。6 總結與展望本論文針對煤礦井下主排水系統自動化程度不高的現狀，研究設計了PLC控制與PC監視相結合的煤礦井下自動排水系統。本文重點介紹了以下幾點內容：（1） 進行系統設計中所使用到的設備的選型工作。首先是根據礦井的涌水量和井深來確定使用水泵的型號和臺數，然后確定排水管道和電動閘閥，電動球閥；根據功能要求選擇一定數量和類型的傳感器，通過估算的輸入輸出點數和要求的PLC的存儲容量及響應速度，確定所用PLC的型號和功能模塊。（2） 設計出了系統控制的流程圖，使用PLC語言編寫了水泵自動控制的部分程序。（3） 利用VISIO繪圖軟件繪制了系統控制的原理圖，由于是初次接觸PLC和礦井排水系統，了解甚微，所以設計中的很多細節部分考慮不周。在郝榕老師的悉心指導下，對結構和部分內容進行了修改，大體上做到了有章可尋。近年來，我國煤炭行業發展迅猛，再加上自動化技術的飛速發展，煤礦自動化生產己成為必然趨勢，而排水系統作為保障安全生產不可或缺的部分，其集中控制的實現對整個煤炭生產具有非常重要的意義。鑒于此，很多工程技術人員對排水系統進行了一系列的研究開發。本文也對其進行了一定程度的探討，但仍有很多方面像傳感器輸入信號的靈敏度、監測模擬的準確性等還有待進于一步研究。而且神經網絡技術、專家系統等先進的控制技術也可應用到煤礦井下排水系統的控制中，使其不斷得到完善，更符合自動化礦山的要求。研制集中控制排水系統的最終目標是將井下排水系統的集中控制納入煤礦的整體集中控制當中，使煤礦生產各個環節均實現集中控制，實現煤礦發展的巨大飛躍。參考文獻[1] 鄭晟、鞏建平、：科學出版社，1999.[2] 顧永輝、（第三分冊）：煤炭工業出版社，1997.[3] ，2008.[4] 郁有文、常健、：西安電子科技大學出版社，2003年7月第2版.[5] 侯友夫、：中國礦業大學出版社，1994年5月第一版.[6] ：煤炭工業出版社，1991年10月第1版.[7] ：煤炭工業出版社，1990年3月第1版.[8] 張廣龍、史麗萍. ，2005年第4期. [9] 譚國俊、韓耀飛、熊樹. ，2006年2月第1期.[10] ，2005.[11] ，2004.[12] ，2005.[13] ，2006.[14] 劉敢、. 山東棗莊，高莊煤礦. [15] 潘忠、. 煤礦自動化，2001年第4期.[16] 張孝穎、張豐敏、張學松. PLC在煤礦井下主排水控制系統中的應用. 中國煤炭，2002年8月第28卷第8期.[17] 郭宗仁，吳亦鋒，郭永編著，人民郵電出版社，2002.[18] 羅振成、2003, 16(4)，P34—36.[19] ，1999, ,P43—44.[20] ，1997, , P7.[21] ，2002,P33—35.[22] Configuring Hardware and Communication Connections STEP7 Manual.[23] SIEMENS. Toolbox for Data Link PGs/PCs to SIMATIC S7.英文原文INDUCTION MOTOR STARTING METHODS AND ISSUESAbstract Many methods can be used to start large AC induction motors. Choices such as full voltage, reduced voltage either by autotransformer or Wyes Delta, a soft starter, or usage of an adjustable speed drive can all have potential advantages and trade offs. Reduced voltage starting can lower the starting torque and help prevent damage to the load. Additionally, power factor correction capacitors can be used to reduce the current, but care must be taken to size them properly. Usage of the wrong capacitors can lead to significant damage. Choosing the proper starting method for a motor will include an analysis of the power system as well as the starting load to ensure that the motor is designed to deliver the needed performance while minimizing its cost. This paper will examine the most mon starting methods and their remended applications.Index Terms: motor starting. Reduced voltage start auto transformer, wyesdelta, power factor correctionI. INTRODUCTIONThere are several general methods of starting induction motors: full voltage, reduced voltage, wyesdelta, and part winding types. The reduced voltage type can include solid state starters, adjustable frequency drives, and autotransformers. These, along with the full voltage, or across the line starting, give the purchaser a large variety of automotives when it es to specifying the motor to be used in a given application. Each method has its own benefits, as well as performance trade offs. Proper selection will involve a thorough investigation of any power system constraints, the load to be accelerated and the overall cost of the equipment.In order for the load to be accelerated, the motor must generate greater torque than the load requirement. In general there are three points of interest on the motor39。s speedtorque curve. The first is lockedrotor torque (LRT) which is the minimum torque which the motor will develop at rest for all angular positions of the rotor. The second is pullup torque (PUT) which is defined as the minimum torque developed by the motor during the period of acceleration from rest to the speed at which breakdown torque occurs. The last is the breakdown torque (BDT) which is defined as the maximum torque which the motor will develop. If any of these points are below the required load curve, then the motor will not start. The time it takes for the motor to accelerate the load is dependent on the inertia of the load and the margin between the torque of the motor and the load curve, sometimes called accelerating torque. In general, the longer the time it takes for the motor to accelerate the load, the more heat that will be generated in the rotor bars, shorting ring and the stator winding. This heat leads to additional stresses in these parts and can have an impaction motor life. II. FULL VOLTAGEThe full voltage starting method, also known as across the line starting, is the easiest method to employ, has the lowest equipment costs, and is the most reliable. This method utilizes a control to close a contactor and apply full line voltage to the motor terminals. This method will allow the motor to generate its highest starting torque and provide the shortest acceleration times.This method also puts the highest strain on the power system due to the high starting currents that can be typically six to seven times the normal full load current of the motor. If the motor is on a weak power system, the sudden high power draw can cause a temporary voltage drop, not only at the motor terminals, but the entire power bus feeding the starting motor. This voltage drop will cause a drop in the starting torque of the motor, and a drop in the torque of any other motor running on the power bus. The to