A thrust magnetic bearing includes a stator having a coil, and a rotor. The stator includes main and auxiliary stator magnetic-pole surfaces. The rotor includes main and auxiliary rotor magnetic-pole surfaces facing the main and auxiliary stator magnetic-pole surfaces. When an electric current flows in the coil, an electromagnetic force in an axial direction is generated between the main stator and rotor magnetic-pole surfaces, and an electromagnetic force in a radial direction is generated between the auxiliary stator and rotor magnetic-pole surfaces. When the rotor is displaced in the radial direction, a radial force that acts on the rotor between the auxiliary stator and rotor magnetic-pole surfaces is increased in a direction of the displacement, and a radial force that acts on the rotor between the main stator and rotor magnetic-pole surfaces is increased in a direction opposite to the direction of the displacement.

A vacuum pump comprises: a ball bearing which supports a rotor; a holding section which elastically holds an outer ring of the ball bearing; and a grease which is filled between the outer ring and the holding section, the grease having a consistency of NLGI No. 1.5 or less.

A vacuum pump comprises: a ball bearing which supports a rotor; a holding section which elastically holds an outer ring of the ball bearing; and a grease which is filled between the outer ring and the holding section, the grease having a consistency of NLGI No. 1.5 or less.

A centrifugal compressor includes a casing, an inlet guide vane, an impeller, a motor, a diffuser and a cooling medium delivery structure. The motor includes a rotor mounted on the shaft and a stator disposed radially outwardly of the rotor to form a gap between the rotor and the stator. The cooling medium delivery structure includes inlet and outlet conduits located to supply and discharge a cooling medium to and from the motor. The shaft has an external shape different than an internal shape of the rotor to form at least one axial passageway between the shaft and the rotor. The cooling medium is supplied through the gap and the at least one axial passageway to cool the rotor.

A centrifugal refrigerant compressor system includes an impeller connected to a shaft. A diffuser is arranged on a downstream side of the impeller and is configured to regulate refrigerant flow exiting the impeller. A magnetic bearing supports the shaft. A sensing element is configured to produce an output relating to a shaft condition. A controller is configured to receive the output and determine an undesired impeller operating condition based upon the shaft condition. The controller is configured to command the diffuser to a desired state in response to the undesired impeller operating condition.

A centrifugal refrigerant compressor system includes an impeller connected to a shaft. A diffuser is arranged on a downstream side of the impeller and is configured to regulate refrigerant flow exiting the impeller. A magnetic bearing supports the shaft. A sensing element is configured to produce an output relating to a shaft condition. A controller is configured to receive the output and determine an undesired impeller operating condition based upon the shaft condition. The controller is configured to command the diffuser to a desired state in response to the undesired impeller operating condition.

A magnetic bearing vacuum pump comprises: a first displacement signal generation section configured to amplify, by a resolution multiplying factor K of K>1, a displacement modulated wave signal modulated according to a displacement of the rotor from a predetermined position to generate a high-resolution displacement signal in a first displacement region including the predetermined position; a second displacement signal generation section configured to generate a low-resolution displacement signal in a larger second displacement region including the first displacement region; a selection section configured to select either one of the high-resolution displacement signal or the low-resolution displacement signal based on an unsteady-state response signal obtained by excluding a steady-state whirling displacement component from the high-resolution displacement signal or the low-resolution displacement signal; and a bearing control section configured to control the magnetic bearing based on the displacement signal selected by the selection section.

A magnetic bearing vacuum pump comprises: a first displacement signal generation section configured to amplify, by a resolution multiplying factor K of K>1, a displacement modulated wave signal modulated according to a displacement of the rotor from a predetermined position to generate a high-resolution displacement signal in a first displacement region including the predetermined position; a second displacement signal generation section configured to generate a low-resolution displacement signal in a larger second displacement region including the first displacement region; a selection section configured to select either one of the high-resolution displacement signal or the low-resolution displacement signal based on an unsteady-state response signal obtained by excluding a steady-state whirling displacement component from the high-resolution displacement signal or the low-resolution displacement signal; and a bearing control section configured to control the magnetic bearing based on the displacement signal selected by the selection section.

A vacuum pump in which a spark is not generated even when a rotor component and a stator component are brought into contact, and an explosive reaction in a vacuum container can be prevented, and a protection portion provided in the vacuum pump are provided. On head part sides of a thread ridge to a thread ridge of a threaded spacer with a narrow clearance of a gas channel therebetween, a protection portion 1a to a protection portion made of non-metal are formed in a peripheral state. A protection portion is similarly formed in the peripheral state also on an inner peripheral surface side of a stator blade spacer opposed to a distal end of a rotor blade with a narrow clearance of the gas channel. The protection portion is formed of non-metal with a sufficient thickness so that metal materials of base materials are not brought into contact with each other even when a rotor blade and a stationary portion are brought into contact with each other.

A compressor assembly is provided. Embodiments of the present disclosure generally relate to compressors used in chiller air conditioning systems for indoor spaces. The disclosed compressors have magnetic bearings that support rotating components. In one embodiment, the compressor comprises a partially segmented thrust bearing stator core. Additional systems, devices, and methods are also disclosed.