Abstract: The crankshaft balance block of reciprocating compressor is to deal with the dynamic balance of the compressor core during operation. When the compressor stops, the movement is in unbalanced state. Due to the existence of the inertia of the movement at the moment of shutdown, the movement will remain in the original state of motion. The reaction force of the refrigeration system to the core is easy to cause the core to shake at the moment of shutdown and generate noise. By studying the vibration noise at the moment of compressor stop. Several schemes to reduce the instantaneous impact energy of the machine core during shutdown are put forward and compared with the experiments. According to different application conditions, the optimal control scheme of compressor shutdown is given to reduce the vibration and noise fluctuation at the moment of shutdown.

Key words: Moment of inertia of the movement, Impact energy, Downtime control, Vibration noise fluctuation