Modelling of the steady state thermal behaviour of a permanent magnet direct current motor with commutator. 3D finite elements study

The aim of this work concerns the development and the validation of a therm al steady state model applied to a permanent magnet direct current motor wi th commutator. The rated power of the machine is 120 W. Design has been rea lized thanks to the thermal modulus of the computation software with the fi nite element method Flux3D. It is shown in this work how it is possible to use only the heat equation to simulate the thermal behaviour of the motor. It implies calculating of new fluid conductivities (considering also all th ermal modes) by comparison of calculated and experimental temperatures. To realize these 3D modelizations, it is necessary to know and to locate all t he losses of the motor which are considered as thermal sources. The experim ental temperatures are given by 40 chromel-alumel thermocouples of 100 mu m diameter located in the rotor and the stator of the machine. Numerical com putations use Dirichlet boundary layer conditions given by an IR camera.