Abstract: In a compressor, the stabilization device for extending the characteristic map consists of a co-rotating ring (2) rigidly connected to the runner blades (1), there being arranged between the ring (2) and the housing (3) of the compressor a recirculation duct (4) which has an opening to the impeller (5) at its rear end in the flow direction, only the previously customary narrow clearance existing subsequently at the rear end of this opening between impeller (5) and wall of the housing. The front edge of the ring (2) in the flow direction can terminate flush with the inlet edges of the runner blades (1), or be axially displaced.