FEM and Lumped Circuit Thermal Analysis of External Rotor Motor

Abstract

In the recent years outer rotor motors, mainly brushless ones, have been the object of increasing attention for some specific applications, thanks to their high inertia and other interesting characteristics. However they are particularly difficult to design from the point of view of their thermal behaviour, as the heat is mainly generated form the internal part of the motor and because some mechanical parts involved in the driving system are embedded in the machine and contribute to the heating or cooling of the machine, consequently they cannot be ignored in the thermal analysis. The production of such advanced machines is very demanding of development time and production cost and therefore a fast and reliable thermal design as a preliminary is greatly beneficial.