CALCULATION OF THE TEMPERATURE-FIELD AT S TANDSTILL OF EXPLOSION-PROTECTED INDUCTION-MOTORS BY 3-DIMENSIONAL FINITE-ELEMENT TIME-STEPPING METHOD

A three-dimensional finite element time-stepping method is presented f or calculation of the temperature field in the rotor of a cage inducti on machine. For the discretisation of the region triangular prisms are used. Losses and eddy currents are determined by separated calculatio ns using the two-dimensional finite element method for bar and end-rin g. The variable permeability is taken into account. Comparisons betwee n calculations and measurements are given for a machine with different end-rings. Rules for an optimal form and position of the end-rings ar e given from experimental and numerical studies.