Abstract: This paper introduces the types of capacity regulation system in reciprocating compressor and their respective application. Meanwhile, it also introduces the related knowledge of compressor rotation unevenness and flywheel torque. The paper takes the commonly used models 2D and 4M in engineering as the research object and elaborates the impacts of the stepless capacity regulation system on the torque of reciprocating compressor. It is concluded that when a new stepless capacity regulation system is installed in the reciprocating compressor, it should be checked whether the compressor torque changes excessively, thus resulting in rotation unevenness exceeding the standard value. This is of certain guiding significance for the selection and check of the compressor and its operation and maintenance.

Key words: reciprocating compressor, stepless capacity regulation system, torque