Abstract <p>This article considers an antisurge protection method based on controlling the running speed of an ac electric motor driving a centrifugal compressor. The reasons for the occurrence and development of surge in centrifugal compressors are considered. Criteria for determining the presurge state of the system are proposed as well as actions to be taken for preventing a compressor accident in variable external conditions. It is proposed to avoid surge by slowing the motor down, that is, by switching to the underlying static head-capacity curve. A simulation model of a compressor with an appropriate control system has been developed. The properties of gases and the design features of the compressor are considered using the MATLAB Simulink modeling environment.</p>