Comparison of shading ring arrangements of low voltage AC contactors

The behaviour of a low voltage contactor is analyzed with nonlinear transient finite element analyses. For a simulation as close as possible to normal operational conditions, a voltage driven model is concerned additionally to a current excited model. A strong circuit coupling takes into account for the eddy currents in the copper shading rings. With regard to optimization tasks, various arrangements of the shading rings are discussed in detail. For the initial design, a comparison of the steady-state current characteristics obtained from the numerical calculations and from measurements shows a very good agreement.