Measurements on Thermal Buffering of Electric Machine Peak Loads With Phase Change Materials

An experimental setup is designed to analyze and compare four different end winding cooling methods for electric machines: air cooling, a phase change material in the end space, a combination of a phase change material and metal foam in the end space and potting of the end space. The potted end space has the best steady-state performance, followed by the phase change material-metal foam combination, the phase change material and finally the air cooling. Transient measurements indicated that the solutions with phase change materials can help to increase peak loads, but they do not outperform the potting solution. This is attributed to the large thermal gradient in the end space, due to which not the entire volume attains the melting temperature during the transient cycle.