The Study On A New Kind Of Planetary Soft Start Method

Machines with great inertia and load will generate added dynamic load which is always larger than the maximum torque of electric motor during the start process. As result of it, the starting current of electric motor is more than 5 to 6 times than its specified current, which would destroy the electric motor or machine transmission device. To solve this problem, researchers in home and abroad have put forward some effective methods, such as Y-△transition, frequency control of motor speed, fluid-flywheel clutch, electric magnetic clutch and so on. To a certain extend, the methods mentioned above can solve the deadweight start, but there are also some difficulties more or less. The electric motor's output power is lower than its specified power at low speed when adopting the method of frequency control, so the electric motor's power would be larger. For fluid-flywheel clutch, the electric motor has high requirement to the supply voltage. For electric magnetic clutch, its efficiency is low. In a word, the common start method is not very perfect.This paper has put forward a new kind of planetary soft start method which can start the load under the condition that the electric motor and the load have been engaging. The main research contents are as following:In chapter 1, research status quo of mechanical soft start on deadweight in recent years in nation and abroad are discussed, advantages and disadvantages are deeply analyzed, research status quo and existent problems of mechanical soft start on deadweight are discussed in detail.In chapter 2, advantages and disadvantages of planetary gear are analyzed, and confirm the planetary gear as the key part of the system. The feasible projects have been given utilizing the freedom transmission between the differential gear and the planetary gear.In chapter 3, electromechanical coupling mathematical model of system is constructed.In chapter 4, the gear system has been optimum designed with the theory of fuzzy, and has gained the optimum solution utilizing the genetic algorithm tool of MATLAB.In chapter 5, the planetary carrier which is the weakest part of the system has been analyzed with ANSYS.In chapter 6, an experiment system has been manufactured, and has done an experiment on it. The result shows that 30%~50% energy can be saved comparing with other methods.The innovative points of this project:⑴Research status quo of mechanical soft start on deadweight in recent years in nation and abroad are discussed, and advantages and disadvantages are deeply analyzed. Then put forward a new kind of planetary soft start method.⑵Electromechanical coupling mathematical model of system is constructed.⑶An experiment system has been manufactured, and an experiment has been done on it in order to optimize certain parameters.⑷A new idea and method for mechanical soft start of motor has been supplied by studying on the method and the device.