Abstract: A system for extracting nitrogen from air to produce a flow of nitrogen includes a compressor for compressing air and an air separator connected to the compressor for producing nitrogen from the compressed air. The compressor is provided with a reducing device for reducing an effective length of the rotatable rotors which acts to compress air in order to cause the compressor to operate at less than full capacity. An internal pressure control regulator operatively associated with the compressor regulates the discharge pressure from the compressor and provides a signal air pressure when the compressor discharge pressure exceeds a predetermined pressure. An external input device allows an external signal indicative of a compressor operating level that is less than full capacity to be inputted and provides a signal air pressure based on the external signal.