Systems and methods for integrally geared centrifugal compressor to maintain rotor concentricity with differing pinion gear tooth counts

An integrally geared centrifugal compressor system for compressing a fluid, the system comprising:

• a pinion configured to be rotated by a bull gear about a rotational axis;
• a rotor coupled to the pinion and configured to be rotated about the rotational axis;
• an eccentric cartridge configured to house a bearing assembly through which the rotor extends to support rotation of the rotor about the rotational axis, the eccentric cartridge configured to seat against an interior surface of a gearbox having a center axis configured to house at least a portion of the pinion and the rotor, the eccentric cartridge configured to eccentrically arrange the rotational axis relative to the center axis of the gearbox;
• an impeller coupled to the rotor and configured to draw fluid into the impeller upon rotation of the impeller, the impeller configured to be rotated about the rotational axis to eject the fluid;
• and
• a volute, wherein at least a portion of the impeller is positioned within the volute to direct the ejected fluid from the impeller into the volute, wherein the impeller is eccentrically arranged relative to the volute.