Power Losses and Thermal Analysis of a Hollow-Shaft Rotor Cooling System

A hollow-shaft rotor cooling system for an automotive traction motor is investigated in this paper. Firstly, various kinds of losses, which include iron, air friction and bearing losses are identified for this cooling system. Secondly, a finite element analysis (FEA) model is constructed to estimate the heat transfer coefficient by considering the experimental shaft surface temperature distribution. Finally, this hollow-shaft cooling is implemented to a traction motor in order to find out the benefits in terms of intermittent and continuous performance.