Controlled refrigeration system

摘要

A controlled refrigeration system includes a plurality of refrigerant compressors fed from a common suction manifold (line). Each compressor is associated with a respective controller. The individual controllers are set to effect the cutting in of its associated compressor at different levels of input voltage from a pressure transducer using digital techniques. The individual controllers each produce respective digital cut-in, cut-out, down-time delay and power-up delay signals. Respective logic circuitry is provided within each controller for producing control outputs which effect the energization and deenergization of the individual controllers. The compressors are turned on and off in sequence as the demand for compression respectively increases and decreases. The power-up delay period differs for each controller so that no more than one is energized at a given time when the system comes on line after a power failure or extended period of shut down.