The Research Of QJZ-1200/3300-8 Multi-Motor Starter Based On The PLC Control System

The research project in this thesis is an electric control part of QJZ-1200/3300-8 Mine Combined Switch, which is coming from Taian Zhong Cheng Mine Automation Co.LTD. As voltage rating promotion and variety of coal mining equipment expand power in our country, From objective requires that the power supply system of voltage of the coal machinery from 1140 levels to 3300, to meet the technical requirements of Mining equipment. However, as our technological backwardness and so on, the supply of equipment about 3300v are mostly dependent on imported. This equipment import prices high, and Technical requirements are not fully satisfy the requirements of our coal mining equipment, And maintenance is not convenient. Based on this case, It is very important to develop the Mine Combined Switch of own property.The research according to the characteristics of our country coal,find the best technology solution, Establish a combination of various techniques and parameters and design the intrinsically safe circuit of the pilot circuit,impressed-current protection system,opposed-voltage protective system,Leakage protection system and human-computer interface, From the effective protection system, ensure the safety of the coal production.The following parts made up the main contents of this thesisFirstly, in the part of Leakage protection system, this thesis design three parts which is the leakage tests before start, the leakage protection when the equipment running, and high Voltage insulation monitoring. In three ways to test the switch to ensure the safety in coal mining equipment.Secondly, designed the current protection system, which protect the system no overload problem, The phase-sensitive methods of protection that used in the current protection systems, and ensure short-circuit current and time of action reliability. short-circuit used the method of phase detection, linear out the relationship between voltage and current.Thirdly, in voltage protective system, this system deal with the Transient overvoltage fault and steady-state Voltage fault. Which sets the circuit parameters, to better meet the requirements of the equipment of mine. Fourthly, Man-machine interface uses touch screen XP70 of LG Company. We set every communication parameters, and configurates with PLC system, That can reliably display states of every unit。System software environment XG500 allows the user to edit, monitor and manage a number of PLC programs in a same project. Procedures can be divided into scanning procedures and tasks procedures. Modular design makes the procedures more user-friendly way to debug, modify, and transplant.