Study On The Equivalent Circuit And Electromagnetic Calculation Of The Canned Solid-rotor Motor With Squirrel-cage

The canned solid-rotor motor with squirrel-cage, which has high mechanical strength, corrosion resistance, long service life, high starting torque, etc., can be applied to nuclear canned pump. Taking this kind of motor as the object, this paper aims at studying the equivalent circuit of it and calculating the analytical expressions of the parameters. In order to proving the accuracy of the equivalent circuit and parameters, we developed an electromagnetic calculation program, and the calculation results are verified. Instead of longer time consuming finite element simulation, it would make the calculation of operating characteristics of this kind of motor easier and faster. Meanwhile, the analytical expressions of the parameters can guide the design of the motor.First of all, the equivalent circuits in the strict sense is given by analyzing the structure and properties of the canned solid-rotor motor with squirrel-cage. The pairwise mutual inductance between the layers of rotor is obtained by equivalent magnetic circuit method. Combined with method of matrix decoupling, it is been theoretically proved that neglecting the mutual inductance between the rotor can and the solid rotor is reasonable. The resistance of stator can is obtained by analytical method of electromagnetic field. Analytical expressions for the impedance of each layer of the rotor side are obtained by two dimensional electromagnetic field theory in other scholar's paper. Finally the simplified and decoupled equivalent circuit and the analytical expressions of different parameters are all given.Secondly, on purpose of verifying the accuracy of the equivalent circuit and the parameter expressions, this paper gives the electromagnetic calculation procedure on base of them, and the corresponding electromagnetic calculation program which could calculate the general operating characteristics of the motor is developed. Thirdly, a finite element simulation model for a prototype is established, by which we analyzed the electromagnetic characteristics and the finite element method of calculating the parameters of the motor is given.At last, the accuracies of the equivalent circuit and the electromagnetic calculation program on base of the equivalent circuit and the expressions of parameters are verified respectively by the results of finite element method and experiment.