Modelling the mechanical and thermal properties of compressed stator windings

This paper discusses coil pressing through which stator windings are compressed at high pressures to enhance the slot fill factor of electrical machines. Deterioration of insulation in compressed windings is investigated by performing quasistatic explicit dynamics finite element simulations. The results obtained from the proposed method are further investigated experimentally to validate the durability of the compressed coils. It is shown that stator windings can be compressed to a certain degree without observing material failure. In order to demonstrate the thermal advantages of densely packed stator windings, both steady state thermal finite element analysis (FEA) simulations and semi-analytical methods have also been studied. A good agreement between analytical and FEA simulations is obtained. It is noted that steady state thermal finite element modeling could be used to predict effective thermal conductivity of stator windings for different slot fill factors.