电梯的电气系统维护毕业设计.doc

电梯的电气系统维护毕业设计 1.毕业实践任务书----------------------------------------------------------1 2.外文翻译 ---------------------------------------------------------------2 3.毕业实践调研报告--------------------------------------------------------10 4.毕业设计说明书----------------------------------------------------------13 5.附录-------------------------------------------------------------------36 6．毕业设计总结-----------------------------------------------------------51 7.参考文献----------------------------------------------------------------35 The history and future of the elevator Lift the invention process Elevator access to peoples lives have been 150 years. 1854, at Crystal Palace in New York Worlds Fair, American ? Elisha Graves Otis ? The first to show the world his invention. He stood fully loaded elevator platform, the command assistant pulled up to the platform can be found on the height of the audience, and then send a signal that helper lift with the ax and cut off the pulling cable. Surprisingly, a lift and did not crash, but firmly fixed in the air - Mr. Otis invented the elevator safety device played a role. All safe, gentlemen. Standing on a lift platform, Mr. Otis waved around people watching. No one would think, this is a safe lift of human history. Lifting tool for transport of goods for human use, staff extremely long history. As early as 2600 BC, the Egyptians built the pyramids on the use of the most original lifting system, the basic principle of this system has remained unchanged: that is, a counterweight is declining, the load platform rise. Fundamental to the early lifting of human-powered tools. 1203, the French coast in a monastery and installed a crane driven by donkey, this ended the history with the human transporting heavy loads. Watt invented the steam engine, British scientists, the crane began to use steam-powered devices. Followed by William Thomson developed ? Hydraulic-driven lift, hydraulic medium is water. On the basis of these lifts, generation after generation