Abstract: Over-temperature and overload often occur when the hydrogen compressor is tested with nitrogen before it is put into use. In this paper, the power of the hydrogen compressor during the nitrogen test was calculated quantitatively according to the thermodynamic calculation, and the power change caused by the mass flow change and temperature change was analyzed. Meanwhile, the expansion work and non-expansion work in the compression process were analyzed specifically according to the relevant theories, and then the power change caused by the change of the working medium type was analyzed and calculated. The reasons for the over-temperature and overload that tends to occur during the nitrogen test were found and analyzed according to the relevant theories.The conclusions of this study may provide some reference for avoiding the above phenomenon.

Key words: compressor, expansion work, non-expansion work, overload, over-temperature