The invention relates to a liquid ring compressor and/or pump, comprising a rotating compressor casing (1), a shaft journal (10) eccentrically located relative to the compressor casing's axis of rotation, with a surrounding bearing (15). One or more compressor wheels (14) with at least one vane are disposed in the compressor casing with the inside of the compressor wheel (14) in abutment against and rotating around the bearing (15) and inlet and outlet ports for the fluid that has to be compressed. When the compressor casing is rotated, a liquid ring (20) is created against the inner wall of the rotating compressor casing (1), which liquid ring (20) together with the compressor wheel (14) forms compression chambers. The liquid ring compressor further comprises at least one magnetic element mounted in the compressor casing (1) adjacent to the compressor wheel (14), where when the compressor casing (1) is rotated, the magnetic element makes the free-running compressor wheel (14) rotate at the same rotational speed as the compressor casing (1).