Analysis of eddy-current contribution to the magnetic field in squirrel-cage induction machines

The study of the dynamic behaviour of an asynchronous squirrel-cage machine from the electric and magnetic fields, cannot be carried out if we neglect the consequence of the eddy-currents in rotor bars. In this paper first the electric and magnetic field of an asynchronous machine have been considered, and the diffusion equation has been discretized by means of the finite element method. Taking into account the winding connections and effecting a suitable variable transformation, the machine equation has been written in the input-state- -output form. The achieved model enables to study of the electric and mechanical machine transient-state, also considering the effect of an uneven current distribution in the rotor windings.