Three Dimensional Eddy Current Field Analysis And Calcution Of Flameproof Motor

The eddy current losses in flameproof motor cause overheating that may be harmful for the insulation, which directly determine the operation life of the motor. The local heating of the structural parts in the end regions, and induced electromagnetic force and torque activated on stator end windings, are the main concerns of motor designer. The end region of the flameproof motor is composed of a very complex three dimensional geometry of the windings. The magnetic field in this region is a completely three dimensional problem. Many research works by solving the end windings field as a two dimensional (2-D) axisymmetric or a quasi three dimensional (3-D) problem have been done. Some author even used analytical method with simplified geometry. Problems in motor end zone magnetic field were put forward many years ago, but because of the characters of the end zone, it hasn't been settled perfectly.Magnetic nodal method and edge element method are widely applied in finite element electromagnetic analysis. Magnetic nodal method has its own shortages and limits, when the solve field has big different magnetic permeability of materials. In the same circumstance, the edge element method has less degree of freedom. Magnetic edge element method is comprehensively used in motor magnetic field analysis for its own advantage.In this paper, a full mathematic model used to calculate end field of flameproof motor by edge element method is presented. The model combines end zone with stepped stator core, expand solved region into the stator and the rotor core and take end effect into account. The model combined end zone with stepped stator core, expanded solved region into the stator and the rotor core. The end structures, the actual shape of end coil and theirs influence to end field calculation are considered accurately. The stator and rotor coils as well as current density distribution in coils are included in the model, and simulated accurately with circuit field coupled method. Taking YBQYS-40B flameproof motor for instance, the end field is calculated at no-load with eddy current taking into account. At last the parameterized calculation program of flameproof motor is programmed.