Experimental study on heat pipe performance and a case study on electric motor cooling

As the increase of electric motor (EM) power, the advanced cooling technology becomes urgent. Heat pipe (HP) is an effective method to cool the EM, where its performance should be considered when designing the EM cooling system. To bridge this knowledge gap, the HP performance, i.e., equivalent thermal conductivity (ETC), is experimentally explored, regarding heating power, inclination angle, heat pipe length, and air velocity. Then a case study on EM cooling is conducted considering the rated and limit operational conditions of EM. Results show that, the ETC would largely vary at different operational conditions and further affect the EM cooling performance. The maximum temperatures of stator-winding assembly at rated condition and running time at limit condition could vary in the ranges of 60.6-64.8 °C and 260-562 s, 61.9-74.5 °C and 245-360 s, and 52.9-61.9 °C and 360-372 s, when inclination angle ranges from -90° to 90°, HP length from 160 to 240 mm, and air velocity from 4 to 8 m/s, respectively. Comparing to the case without HP, the HP application could largely decrease the maximum temperature by 55.0 °C and increase the running time by 165 s.