The Design Of Long-primary Linear Induction Motor And Research On Electro-magnetic And Thermal Field

Linear motor is a kind of electric drive that can transfer electric energy to linear mechanical energy directly. Every rotating motor has a homologous linear motor in principle, because they have similar principle of work. Linear motor has entered into a independent application stage and all sorts of linear motor have been popularized since 1970. As one kind of linear motor, the long-primary linear induction motor (LIM) has also been applied in some domain. In fewness special field, it has some unique advantages. This paper has researched the theory of the long-primary LIM and designed a model machine.Firstly, based on existing research condition summarized, the air-gap magnetic field and the design traits of the LIM have been analyzed. The equivalent circuit's dissimilarity of the LIM has also been analyzed to supply foundation for electromagnetism design.A method on the electromagnetism design of the long-primary LIM is brought forward on the base of the design task confirmed. The final design scheme is determined, the model machine's parameter is obtained by compiling computation program, and the model maching is manufactured.Secondly, the electro-magnetic field for the LIM at blocked-rotor process is simulated by the finite-element method (FEM). The flux distribution in the motor is obtained, the air-gap flux density and tooth flux density are analyzed, the tangental force and normal force for the secondary are calculated, and the esperiment for the LIM at blocked-rotor is taken. Meanwhile, the tendency of the motor's performance is proceeded when the thickness of air gap have been changed, some favorable conclusion is obtained.Finally, the transient thermal field model for the LIM is developed based on mathematic model and suppositions, the model enables the analysis of the transient thermal during 10s rotor blocked, during 10min disconnection of motor and during repeated next 10s rotor blocked. In the three processes the important nodes and tooth-top temeparature along lengthwise, Middle-yoke temperature along lengthwise and Core temperature from yoke to tooth-top are analyzed. Results of calculations are compared with experimental results derived from a prototype motor and the correctness of the calculation model and calculation results are verified.