Heat transfer enhancement in the unfinned frame of an externally cooled induction motor

This article describes an experimental investigation to study the effect of guide vanes on the heat transfer coefficient over the unfined frame of an externally cooled induction motor Guide vanes with various heights and spac ings have been rested. In general, the guide vanes modify the airflow over the frame, hence increasing the heat transfer coefficient. An optimum heat transfer case is found, for which the average heat transfer coefficient is 70% higher than for the case without guide vanes. The velocity distribution s of the airflow are measured for comparison with the heat transfer coeffic ient fields. The location of the terminal box is optimized, resulting in a 1 degrees C: drop in the average temperature rise of the coil motor Finally , the results of this research are applied to a real induction motor and it s average coil temperature becomes 9 degrees C lower than that of a commerc ial motor